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mbc
10-31-2010, 08:11 PM
The last few days, the Van has been running a little hotter than I'm comfortable with. After 10 minutes of trouble shooting, here's what I've determined so far.

I'm fairly certain that there are:
No leaks.
No coolant loss.
No bubbling.
Water pump shaft has no play.
Belt is okay and not loose/ slipping.
Ign timing within specs.

It's possible that:
There's blockage within the (original) radiator.
The thermostat is faulty.

However,the upper radiator hose is hot and the lower hose is warm (not cold).

I looked for the Bill Maley manual to determine the direction of coolant flow, but it's now gone:(:. My logic and experience tell me that the Van has a sticking T-stat based on the symptoms, but the reversal of hot and cold hoses has led me to post here.

Can anyone confirm the direction of coolant flow? Has anyone here experienced these symptoms?

llamavan
10-31-2010, 09:02 PM
The coolant flow direction is located here (http://www.toyotavantech.com/forum/showthread.php?67-Getting-to-know-all-the-coolant-hoses-of-your-Vanwagon!&p=321#post321).

What you describe sounds normal (that is, hot upper, warm lower). Because the lower hose isn't cold, I'd suspect the thermostat first. If a new Toyota t-stat doesn't do the trick, I'd be all over the radiator next. Even partially clogged radiators noticeably compromise our vans' cooling.

Gwen

NEC
10-31-2010, 09:08 PM
x2

mbc
10-31-2010, 09:18 PM
cool thanks,

I totally forgot to look up your thread.:doh:

The T-stat is from Napa (170*)and is about four years old. I read all of the threads regarding the use of OEM T-stats, but mine was already in and I haven't had any issues with any Napa T-stats.

I wonder if Toyota sells 180* T-stats for the Van (attn NEC). I had a 195* one in the Van years ago, and the temp gauge was constantly above the half-way mark. Too high for me.

I'll take a closer look and report back.

P.S. I still haven't had the time to remove the rear heater either. I'm not one to turn down work.

It will have to wait until the weekend anyway, fortunately, I'm very busy with work.

llamavan
10-31-2010, 09:51 PM
My experience with the NAPA t-stats is:

• they tend to run slightly warmer than OEM
• they don't last as long as OEM
• when they fail, they fail closed (OEM have gone both ways for me)

T-stat time!

Gwen

mbc
10-31-2010, 11:18 PM
After thinking about it some more, I surely hope that it is indeed the T-stat. I'd hate for it to be a clogged / worn out radiator or...

I neglected to add that the Van only seems to heat up under a heavy load, or occasionally after shut down. the temp gauge never goes into the red, or even that space before, but hot enough to cause alarm. Oh yeah, the fan clutch roars like a lion...it's been my Van's saving grace.

I'll get a Toyota T-stat in the morning (fingers crossed).

NEC
11-01-2010, 04:23 PM
The oem only makes one temperature range tstat for our vans. Mine never gets past 50% on the dial no matter how hot it is outside or how hard I push it. If you still have issues after you rule out the thermostat and you are sure your fan clutch is working I would suggest getting your radiator re-cored.

mbc
11-26-2010, 10:33 PM
I figured I'd give a quick update.

I've found that the existing thermostat works fine. I could tell when it was opening during last week's cooling system flush. With the radiator petcock removed and the engine running, there was good water flow through the system too. I used a garden hose (with low water flow) inserted into the filler neck while running the engine and both heaters. Each time I revved the engine a little, the volume of water leaving the system increased indicating decent flow.

No longer running hot... for now.

Cornato
02-28-2011, 06:41 PM
My thermostat has the opposite problem. It won't go past the quarter mark no matter how long I drive. Stuck open? And if it is, is that such a bad thing?

timsrv
02-28-2011, 09:34 PM
It's not terrible. With a working 180 deg t-stat and a good working cooling system the engine will run at about about 180-205 deg F (if measured from the same spot as your stock temperature sending unit). Assuming your gauge is reading accurately, 200 deg F is about the middle of the scale.

Regardless of where the needle lives, If you heater is working good and the engine is not overheating then I'd assume the thermostat is working fine. If this is the case and your needle is not in the middle, then perhaps your temp gauge is just a little off (might just be normal for your van). On the other hand, if the heater only blows luke warm then I'd recommend replacing the t-stat. Just keep in mind that more internal engine wear occurs at temp ranges outside of the norm. It's not such a big a deal on an old engine with lots of miles, but having a good working cabin heater this time of year would be enough motivation for me. Tim

Cornato
03-01-2011, 08:58 AM
Well, the heater works just fine I just would like to replace anything faulty on the van. I'm also having problems with it kicking into overdrive and I talked to a local toyota mechanic and he said, the thermo is stuck open so the engine is abnormally cold not allowing the temperature sensor to register right, which has to be a certain temperature to allow the overdrive switch engage.

So I blocked off almost all of the radiator from receiving any air flow and drove pretty far on a decent day (mid 70's), and no change. What does this indicate?

timsrv
03-01-2011, 05:03 PM
It indicates a problem with your overdrive system (not your cooling system) I responded to your OD related question HERE (http://www.toyotavantech.com/forum/showthread.php?330-Overdrive-issues). Tim

skibum
03-14-2011, 01:07 AM
I would like to reaffirm the choice of the Toyota thermostat as opposed to Napa. I have replaced my thermostat with the Napa one a few times and have always has widely varied temperatures (1/3 to 7/8 on the guage). I drive in the mountains and have to grab second gear on steeper grades, both for the power and the cooling.

I just had an overheating episode that either started with, or caused the water pump to go out. I replaced the water pump, so I can't say for sure, but I also replaced the thermostat with a genuine Toyota and now I run at about 1/4 on the guage and only up to about 1/2 when it's working. I've had the van for close to 75,000 miles, so I believe that the change was the thermo, not the pump.

FWIW,
Scott

MonTex
03-20-2013, 01:47 PM
My '89 4WD/automatic seems to run on the hot side, above the half-scale on the temperature gauge. I have taken my radiator to the radiator shop to have it gone through, which was returned to me with a clean bill of health after about $60 for the cleaning/flushing, rodding-out job. I was told that it 'wasn't in bad condition' by the radiator shop personnel.

I have also installed the following new Toyota parts: thermostat/O-ring gasket/water pump/water temperature sensor/radiator (coolant) cap/upper & lower radiator hoses and new timing gears chain. I also recently installed a new head gasket and had the head gone through by a very competent machine shop. The head was in good condition, but had it gone through anyway. I have verified that my timing and timing advance is correct. I also squeezed my lower radiator hose several times, after warm-up, with the coolant cap off to ensure that no air bubbles existed in my coolant system.

On a warm 70 -75 degree day, without my A/C running, my temperature gauge reads a bit above half-scale - about a needle's width above half scale to half-way between half-scale and the upper-end of the 'white/normal' part of the scale. I reference that my engine is running 'hot' after reading many posts on this forum whereby reports of normal operating temperature reports seem to be between 1/4-scale to 1/2-scale on the water temp gauge. I tried running with my front heater on, which does blow warm air, but this does not seem to lower my operating temperature. I have also verified that my fan clutch is working OK, as I can hear it rev up and down as it should.

However, I have noticed that if I top-off my coolant to the top of the filler neck, and verify that my coolant level in the coolant reservoir is at the high mark, after driving around for a few miles, I am losing a bit of coolant. When I check my coolant reservoir, it remains at the high mark. I have not replaced the hose from the coolant reservoir to the coolant filler neck (but perhaps I should do so).

Given that I live in the Los Angeles area, where it gets quite warm in the summer, with lots of stop-n-go traffic, I am really trying to keep my operating temperature at a more 'normal' temperature - not to exceed half-scale on my water temp scale.

I have read of people re-coring their radiator with a (the) larger more-efficient core that is available at a Yuba City, CA radiator shop, which by-the-way is also available at the radiator shop that I visited when I had my existing radiator gone through. The owner of my local radiator shop told me that there is some risk with using the larger radiator core with an extra row, in that the larger radiator core cannot accept 'enough' solder where the radiator side tanks meet the core, and thereby the risk of the tanks leaking because of the reduced amount of solder that can be used with this larger than stock radiator core.

I am reaching-out to forum members for any additional comments/help. Is there anything that I am missing here?

Thanks in advance for your comments and advice.

timsrv
03-21-2013, 01:09 PM
It sounds like you have addressed everything. I wish I could offer an easy remedy, but I've been here too. With these vans I've found cooling issues are typically easy to remedy with few exceptions. Unfortunately it sounds like you may have one of those exceptions :confused:. Before doing any more, I would recommend installing an accurate temperature gauge with numbers so you can monitor/compare with the stock gauge. My 2wd cargo van had a problem that wasn't so easy to diagnose/repair. After replacing several stock parts with no joy, I installed a custom radiator with a high efficiency core. Yes it helped, but didn't completely solve the problem. Next I put in electric fans & a homemade shroud.......that helped too, but at times (typically when air conditioning was running) it would still run hot. Next I installed a heater core from a Previa behind the vent holes on my front bumper (tied into my cooling system) and this helped too. After that the problem was almost gone except when driving up steep grades on hot days with my AC on. Next I fabricated & installed an air scoop and installed down low in front of my radiator. This helps direct air up and into the radiator/engine area when I'm driving. I haven't been in a situation yet since installing the scoop to see if the problem has been completely solved. To this day I still haven't figured out why this particular van has been so difficult to keep cool. Yes I haul around a lot of weight (almost 3,000 lbs) but I've done this with other vans with stock cooling system components and had no problems. Tim

MonTex
03-21-2013, 03:01 PM
It sounds like you have addressed everything. I wish I could offer an easy remedy, but I've been here too. With these vans I've found cooling issues are typically easy to remedy with few exceptions. Unfortunately it sounds like you may have one of those exceptions :confused:. Before doing any more, I would recommend installing an accurate temperature gauge with numbers so you can monitor/compare with the stock gauge. My 2wd cargo van had a problem that wasn't so easy to diagnose/repair. After replacing several stock parts with no joy, I installed a custom radiator with a high efficiency core. Yes it helped, but didn't completely solve the problem. Next I put in electric fans & a homemade shroud.......that helped too, but at times (typically when air conditioning was running) it would still run hot. Next I installed a heater core from a Previa behind the vent holes on my front bumper (tied into my cooling system) and this helped too. After that the problem was almost gone except when driving up steep grades on hot days with my AC on. Next I fabricated & installed an air scoop and installed down low in front of my radiator. This helps direct air up and into the radiator/engine area when I'm driving. I haven't been in a situation yet since installing the scoop to see if the problem has been completely solved. To this day I still haven't figured out why this particular van has been so difficult to keep cool. Yes I haul around a lot of weight (almost 3,000 lbs) but I've done this with other vans with stock cooling system components and had no problems. Tim

Thanks, Tim:

After re-reading the head gasket issues thread, I too am losing a cup or two of coolant out of my engine - yet not from out of my coolant reservior. I'm now on the hunt for coolant leaks around the engine compartment and elsewhere. I have ordered a new coolant reservoir cap to filler-neck hose just in case...it seemes a but too soft for my liking. I'll share what I may discover, leak-wise. Nothing is quite obvious at this writing.

Regarding air inlets to cool the engine area, there are a variety of aircraft fuselage air inlet scoops available at the URL below. Might be an interesting custom look to mount one or more of these on the LF and/or RF quarter panels of our vans!

http://www.aircraftspruce.com/categories/aircraft_parts/ap/menus/ap/vents_inlets.html

- Carl

timsrv
03-25-2013, 10:14 PM
I would like to reaffirm the choice of the Toyota thermostat as opposed to Napa. I have replaced my thermostat with the Napa one a few times and have always has widely varied temperatures (1/3 to 7/8 on the guage). I drive in the mountains and have to grab second gear on steeper grades, both for the power and the cooling.

I just had an overheating episode that either started with, or caused the water pump to go out. I replaced the water pump, so I can't say for sure, but I also replaced the thermostat with a genuine Toyota and now I run at about 1/4 on the guage and only up to about 1/2 when it's working. I've had the van for close to 75,000 miles, so I believe that the change was the thermo, not the pump.

FWIW,
Scott

I can confirm it was definitely the thermostat. My 86 van was having an issue with super long warm-up times so I pulled the thermostat & found it stuck open. After looking through my boxes of parts I couldn't find my extra Toyota thermostats (6 months after moving finding stuff still sucks). Anyhow, after about an hr of looking I gave up and called Napa. I asked for their most premium thermostat and got a Tama Enterprises Co. Part #154-2403 "made in Japan". It looked pretty good & even had a jiggle valve. I compared to the Toyota thermostat and although a bit different it looked to be the same depth & travel. Long story short I installed it and immediately started having the same problem as Scott. My new fan clutch (which I know to be adjusted correctly) would only run sometimes even though the gauge was getting up to 3/4 (this means the radiator temp was already cool but the system was lacking circulation).

This weekend I picked up a Toyota thermostat part #90916-03046 (was actually a couple bucks cheaper than the Napa one) and that completely solved the problem. Now my temperature gauge stays rock solid at 1/4 - 3/8 of the scale. It was warm today and I even ran my AC for a while. Tim

EdCrono
07-10-2013, 03:29 AM
Hi Tim. I got stuck in traffic today in the hot (85f/h) part of the day (1:30 PM-2:00 PM). And my temp started slowly going up. I got to my destination and was I was idling, waiting for this parking spot to open and my gauge got a little higher than 3/4 of the way, then I shut the engine off untill the parking spot got open so I could park my Van.

Next I raised my seat to check on the engine and bubbling water was coming out the reservoir tank. I left it parked there until almost sunset and then put some water in the radiator. I started the engine so the water could flow and I could pour some more in but it didn't take anymore, and for some reason I felt Like I didn't put enough. Anyways, when the engine was warm enough I put the radiator cap back on and put water in the reservoir tank to "full" line. Then I drove home 15 miles away and it did not heat up. Of course, weather temperature was a lot cooler (68f/h), but I noticed the temp gauge in my van dancing at the halfway marc when it is usually at 3/4 of the way.

My van has been sitting for a while and today I moved it...

I'm planing on getting a new tmstat from the dealer in the morning. Do you think that could be he problem? may be a closed tmstat? Any inputs would be helpful as I'm trying to do this the right way. :?:

Thanks! :dizzy:

timsrv
07-10-2013, 04:04 AM
Replacing the thermostat is a good 1st step when chasing cooling issues. It's a moving part & one of the most likely to fail. It's also cheap and fairly easy to change. It may not solve the problem but if nothing else you can rule it out and feel confident with it for at least a few more years.

Were you running AC when this happened?

MonTex
07-10-2013, 02:40 PM
Replacing the thermostat is a good 1st step when chasing cooling issues. It's a moving part & one of the most likely to fail. It's also cheap and fairly easy to change. It may not solve the problem but if nothing else you can rule it out and feel confident with it for at least a few more years.

Were you running AC when this happened?

I too have had cooling system problems with my '89 4x4 van (automatic). The original radiator has been 'rodded-out'/checked and tested at a local, reputable radiator shop, and was given a good bill of health. It was re-installed, along with a new Toyota thermostat (P/N 90916-03046), new Toyota Upper/Lower radiator hoses, new Toyota water pump, new Toyota fan clutch. The water temp sensor is the original one. The radiator fan clutch operates as it should. New (Prestone-Green) coolant level remains constant in the system. No leaks detected after long warmup times.

My water temp on the factory gauge reads 3/4-scale (with the A/C off), on the "white" part of the scale, with outside ambient air temps around 80-90 Deg. F. (here in Southern California). I'm wondering if my gauge could be off, or the water temp sensor may be out of spec. The fan shroud is complete, intact, and on correctly.

Thoughts?

Who reading this has placed a 4-row core into their van? If so, was it beneficial? My radiator shop can retrofit a high-efficiency 4-row core onto my original radiator tanks, but I was told (cautioned) that a larger 4-row core would accommodate less solder at the tanks than the original 3-row core
has. This may result in the radiator being less reliable over time.

Thoughts?

EdCrono
07-10-2013, 02:44 PM
Replacing the thermostat is a good 1st step when chasing cooling issues. It's a moving part & one of the most likely to fail. It's also cheap and fairly easy to change. It may not solve the problem but if nothing else you can rule it out and feel confident with it for at least a few more years.

Were you running AC when this happened?

No, the A/C was off. The dealership said the Tmstat will get here this afternoon. I've been driving around today, but then again the temp is a lot cooler today 'cause it's cloudy.

I'll keep you posted. I'm planning of flushing the raditor really good, putting that new tstat on and filling it up with coolant vie water.

Thanks! :thmbup:

joegri
07-10-2013, 06:31 PM
after all this talk about t stats and radiators and having much of the same problems and symptoms that we all are having i went ahead and ordered a new t stat from the toyota dealer today. i had to think long and hard about this and i remember putting in an aftermarket t stat a long time ago like 7 years.but i didnt drive this van cuz it was under construction so i put a new aftermarket t stat in it like feb and still the same symptoms continued to this day.and my previous van had a toyota t stat in it that opperated perfectly normal with no problems. so long story short i,m guessing in the case of t stats ya gotta use original equipment .i,m sorry for jumping in on this thread but, i had to let you guys know i have many of the same situations that you do and i will report back back my findings after i put the new one in! i just gotta make some time(thankfully i,ve been real busy with the carpenter work these days.

timsrv
07-10-2013, 10:32 PM
Who reading this has placed a 4-row core into their van? If so, was it beneficial? My radiator shop can retrofit a high-efficiency 4-row core onto my original radiator tanks, but I was told (cautioned) that a larger 4-row core would accommodate less solder at the tanks than the original 3-row core
has. This may result in the radiator being less reliable over time.

Thoughts?

Over the years I have had several high efficiency extra core radiators custom built. I have never had a problem with any of them. I have however noticed a marked improvement regarding cooling problems. I used to build hot rods and in many cases the extra rows were the only solution that actually worked. I have never heard before from any radiator shop that there was a down-side. In fact, quite the opposite. When brainstorming with radiator shops on how to address cooling system problems I have had multiple radiator guys recommend this as the best solution.

I'm not disagreeing, I'm just very skeptical. If that turns out to be true it will be news to me. As for putting one in a van, I had a custom high efficiency 4 row radiator built for my 89 van in 2005. There was an immediate marked improvement with cooling & I'm still running that same radiator 8 years later (hasn't sprung a leak yet)..........knock on wood Tim

thetoaster
07-10-2013, 10:44 PM
I had some overheating issues a few years ago. The van would run just a little hot but only occasionally. After parking it I could hear overflow gurgling into the overflow tank. So I did what I would always do in that situation and ordered a new tstat from the dealer. While I was waiting for it to arrive I happened to talk to a buddy of mine who's a pretty damn good mechanic. He suggested first replacing the radiator cap for any and all cooling issues with any vehicle. So I went to Napa(or some such) and picked up a new radiator cap. I put it in and haven't had a single overheating or overflow issue since. I actually still have the tstat sitting in the glove box for the day it's actually needed. Obviously, your mileage may vary.

On a side note, this new server is fast. Me likey. Thanks Tim.

timsrv
07-10-2013, 11:18 PM
Good point. Sometimes the best solutions are also the simplest. Every time you pull the radiator cap you should inspect the rubber gasket & check the seal surface inside the filler neck. Sometimes the seal surface gets divots or bumps from corrosion. The cap is designed to keep pressure at around 13 psi, but if the seal to the cap is compromised it won't hold any pressure. Tim

PS: Yes, the new host is awesome! Although I don't deserve credit. Gwen (llamavan) did all the real work. Tim

MonTex
07-11-2013, 01:01 AM
Thanks for weighing-in on this, Tim.

EdCrono
07-12-2013, 02:32 AM
..update. I got my new thermostat from Toyota. I drained my radiator. Put the new tstat on and now the temperature gauge hangs around the 50%, 55% neighborhood when I drive, which has me worried because the weather has been a lot cooler since I put the new tstat on.

Now, I noticed I made the mistake of not draining the engine block like I did with the radiator and since there was water in the system before instead of coolant I guess now I have a mix of coolant and old water:wall:. No wonder, I was reading the manual for the van today and it says you need about eight quarts of coolant and I could only fit four quarts :doh: .

So my questions now are: should I do the complete coolant drain this time, and then refill with 100% coolant?

..and also, after driving a little today, maybe 15 minutes or so, I checked my radiator hoses. The upper one was really hot (could not keep a hold on it), and the bottom one was hot, but definitely not as hot as the upper one. Is that normal? I read somewhere it's a sign of a shut closed thermostat.. but I just replaced it! :?: No bubbling coolant or leakege anywhere.

Like I mentioned before, it has been a lot cooler these last two days, but I'm worried that when it gets hot again the temp gauge will go up again.

Any thoughts or suggestions will definitely help.

Again, Thanks!

EdCrono
07-12-2013, 02:34 AM
Oh, forgot to mention I replaced the radiator cap as well. :doh:

timsrv
07-12-2013, 04:45 AM
50 - 55% on the gauge can be normal. If it stays below the 75% mark I wouldn't worry about it. If you want to know the exact temp get a meat thermometer & check the temp in the filler neck (warning, removing the radiator cap from a hot engine can be dangerous). Normal operating temp is 180-200. It's typical to see it on the higher side when the weather is hot. Yes, it's normal to have the hoses hot like you observed. The upper hose has ~200 deg coolant flowing inside of it when the van is at normal temp. The lower hose represents the temp of the coolant AFTER it's been cooled by the radiator. Actual temps will vary depending on weather conditions & how hard the engine has been working..........but should be noticeably cooler than the top hose.

As for the ratios of coolant to water, the only way to get it right on initial fill-up is to completely drain the system then put the correct mix ratio in. If your ratios are off, you can use an ethylene glycol refractometer like THIS ONE (http://www.amazon.com/Magnum-Media-RHA-100ATC-Antifreeze-Refractometer/dp/B009197CB6/ref=sr_1_2?ie=UTF8&qid=1373621366&sr=8-2&keywords=refractometer+antifreeze) to determine correct ratios & adjust. Most auto parts stores have cheap ones LIKE THIS (http://www.amazon.com/Stanley-Proto-JFFCC3-Antifreeze-Tester/dp/B00BNSJCAC/ref=sr_1_3?s=hi&ie=UTF8&qid=1373621474&sr=1-3&keywords=tester+antifreeze) that aren't as accurate, but will get the job done. Just remember that water cools better than antifreeze, so don't go above 50% (-34 deg) mix ratio. This could also be reason you are seeing the temp gauge reading higher. Of course the down side of 100% water is it will create corrosion issues & will freeze-up/break your block in the winter (assuming it gets cold enough where you live). Tim

EdCrono
07-12-2013, 10:56 AM
.. Just remember that water cools better than antifreeze, so don't go above 50% (-34 deg) mix ratio. This could also be reason you are seeing the temp gauge reading higher. Of course the down side of 100% water is it will create corrosion issues & will freeze-up/break your block in the winter (assuming it gets cold enough where you live). Tim

Thanksagain for replying Tim. I hear that water also boils faster during a hot day, while the coolant don't and eventually water evaporates, what do you think? Do you think I should drain the whole thing and fill it with the already mix 50/50 coolant?

Thanks again! the progress has definitely gone for the better :sfr:

timsrv
07-12-2013, 11:59 AM
The pre-mix is all I use anymore. I used to scoff thinking it was a waste of money.........until I lived in a place that had acidic water. Unaware of the water's destructive properties I used hose water (as I always had) to mix my own coolant ratios. We lived there for 8 years & that water found it's way into every one of my vehicles. I only discovered this a few months before we moved. As a result I have had to flush my systems, have my radiators rodded out, and have switched to the pre-mix. An alternative could be mixing with demineralized water. Tim

PS: Yes, water will boil faster than ethylene glycol, but for this application that is typically not a concern. If you have a sealed system water won't boil unless it's severely overheated. At atmospheric pressure water boils at 212 deg but at 13 psi it boils at around 245 deg.

EdCrono
07-12-2013, 01:02 PM
The pre-mix is all I use anymore. I used to scoff thinking it was a waste of money.........until I lived in a place that had acidic water. Unaware of the water's destructive properties I used hose water (as I always had) to mix my own coolant ratios. We lived there for 8 years & that water found it's way into every one of my vehicles. I only discovered this a few months before we moved. As a result I have had to flush my systems, have my radiators rodded out, and have switched to the pre-mix. An alternative could be mixing with demineralized water. Tim

PS: Yes, water will boil faster than ethylene glycol, but for this application that is typically not a concern. If you have a sealed system water won't boil unless it's severely overheated. At atmospheric pressure water boils at 212 deg but at 13 psi it boils at around 245 deg.


Woow, that is a pretty good lesson to learn from, thanks for sharing it Tim :thmbup:. I'm flushing everything out and refilling w/ the coolant-antifeeze all in one, all the way to the top. Better be on the safe side since we still have the hotter days of the summer still ahead.


Thanks again Tim and everyone that has been commenting and sharing their experiences, I've aponged a lot of knowledge and gotten to know my van better than any other car I've owned :drive:

micah202
05-24-2016, 10:04 PM
I can confirm it was definitely the thermostat. My 86 van was having an issue with super long warm-up times so I pulled the thermostat & found it stuck open. After looking through my boxes of parts I couldn't find my extra Toyota thermostats (6 months after moving finding stuff still sucks). Anyhow, after about an hr of looking I gave up and called Napa. I asked for their most premium thermostat and got a Tama Enterprises Co. Part #154-2403 "made in Japan". It looked pretty good & even had a jiggle valve. I compared to the Toyota thermostat and although a bit different it looked to be the same depth & travel. Long story short I installed it and immediately started having the same problem as Scott. My new fan clutch (which I know to be adjusted correctly) would only run sometimes even though the gauge was getting up to 3/4 (this means the radiator temp was already cool but the system was lacking circulation).

This weekend I picked up a Toyota thermostat part #90916-03046 (was actually a couple bucks cheaper than the Napa one) and that completely solved the problem. Now my temperature gauge stays rock solid at 1/4 - 3/8 of the scale. It was warm today and I even ran my AC for a while. Tim


....fan clutches have an adjustment?

..I'm on my 3rd installation of a brand new fan-clutch,, the most recent is an Aisin,, still doesn't seem to be fully engaging as seen on TV (your vid)

...is there something I'm doing wrong with my fan clutches?...seems like an easy installation. :?:

timsrv
05-25-2016, 12:17 AM
....fan clutches have an adjustment?

Not really something I'd recommend just anybody try, but I've adjusted them before. Back when I was experimenting with AM fan clutches I did this on a premium Napa brand (TRW I think?). If opened up there's screw slots inside that allow for adjustment (to make fan engage at a different temp), but this one was riveted together. The fan was engaging late, and I didn't want to drill rivets and/or mess around in the silicone goo, so I adjusted externally by relocating outer side of the bimetal coil. There wasn't a groove in the right spot so I cut a new one and dialed it in that way. It's the one I was running in this video (http://youtu.be/4sHCeyOrncA), and I had it dialed in right where I wanted it. Sadly it failed after only a few thousand miles so I got a Hayden AM fan clutch. That one was adjusted correctly out of the box, but it leaked out all the silicone and failed after only a few thousand miles too. At that point I had enough of the AM clutches and went with the Aisin (http://www.toyotavantech.com/forum/showthread.php?1725-Fan-fluid-coupling-(fan-clutch)&p=13762#post13762). That was 20 something thousand miles ago and it's still performing well. Here's some pics of that riveted one I adjusted:

http://i8.photobucket.com/albums/a23/timsrv/TVT%20pics/cooling%20system/IMG_2630_zps73b4cc7f.jpg

http://i8.photobucket.com/albums/a23/timsrv/TVT%20pics/cooling%20system/IMG_2629_zps3489f427.jpg

http://i8.photobucket.com/albums/a23/timsrv/TVT%20pics/cooling%20system/IMG_2631_zpsc9cf60b7.jpg

timsrv
05-25-2016, 01:53 AM
..............I'm on my 3rd installation of a brand new fan-clutch,, the most recent is an Aisin,, still doesn't seem to be fully engaging as seen on TV (your vid)

...is there something I'm doing wrong with my fan clutches?...seems like an easy installation. :?:

I guess it depends on operating temperature. With the van shut-off, put a temperature probe in the proximity of the front of the fan clutch and put a meat thermometer in the filler port. If you don't have or can't afford a professional grade "remote probe" thermometer, they make them for cooking roasts and things and the range is perfect for automotive use. Anyhow, secure it in the area between the fan clutch and the radiator and hold your van at a high idle. As the temperature rises the bimetal coil on the front of the clutch rotates (changes valving inside the clutch). At some point the clutch fan will begin to engage (probably around 180° F). If the clutch fan is working correctly it will only engage as much as needed to stabilize temperature between radiator and fan. If temp in this area continues to rise, but the clutch continues to slip, then it's a defective clutch. If the temperature stabilizes, then the clutch is doing it's job (it's designed to regulate air flow based on temperature)

If the engine coolant temperature continues to rise beyond a normal range (205°+), but the temp in front of the fan remains low & stable, then there is a circulation problem (coolant and/or air). Coolant circulation problems can be caused by a plugged-up radiator, an aftermarket t-stat, a stuck thermostat, or excessive rust/scale build-up inside the block (foreign material). If you've recently replaced the t-stat with an OE, then you can probably rule that out. If the coolant is nice and clean, then you can probably rule out rust/scale. You can get an indication of radiator condition by removing the top radiator hose & inspecting the visible core/tube openings for solder bloom (http://i8.photobucket.com/albums/a23/timsrv/TVT%20pics/cooling%20system/Solder%20Bloom_zpseols1lyf.jpg).

Air circulation problems can be debris or anything preventing air flow through the radiator. If air cannot flow through the radiator, the fan will suck cooler air from surrounding areas. Since the clutch is regulated by temperature, it will never engage if the bimetal coil stays cool. One common cause of air flow restriction is road debris stuck to the front of the radiator/condenser. Since air will follow the path of least resistance, if you have a fan shroud that's missing parts or that's missing altogether, this will allow the fan to suck air from everywhere except through the radiator (make sure your shroud is there and intact). Note: These vans have 2 piece fan shrouds, both pieces MUST be there. Tim

micah202
05-25-2016, 06:27 PM
...thanks Tim,, got the remote thermo today,, it'll be good to get to the bottom of all this :dizzy:


....I thought I was done and dusted when I got the Aisin ,, what you've given above should help.
....then again, I also thought fan clutches transferred the engine heat through their mount with the engine. :?:

..prolly should be in a 'cooling system' thread, lotsa valuable deets beyond thermostats! :thmbup:

micah202
05-29-2016, 05:02 PM
,

,,the remote thermo was an interesting and informative experiment.
I drilled a small hole in the cowling, so the sensor was ~3-4'' from the center of the fan. I had already calibrated my thermostat and temp guage to know where 180 deg is, so did most of my observations in driving.
I've been starting and running ~180 usually,, but on a longer drive, 40 min or more, temps would rise but the fanclutch wouldn't engage.As this happened I could now see that the front heat was only ~125deg or so.... I've returned 2 fan clutches in error! I recall once stopping by my parts dealer when the car was very hot, but the clutch wasn't engaging,, the car sat a few minutes,, and the clutch worked- only time! Now I see that temp rises enough when the van's stopped,, enough that the fan clutch engages :doh:

So now, a new radiator's in place,,, and I believe a HUGE BONUS! I was quietly concerned about a small but steady loss of coolant,,, concerned it was head gasket issues, but not seeing typical telltale white smoke, and no water in the oil. In changing the radiator, I found a cracked bleeder hose ,between filler and top of radiator....here's hoping that's the end of fluid loss! :thmbup:


Tim,, thanks for all you helpful direction. Without you, I'd be totally lost as to where to bring some very thilly questions, necessary to ask in order to bumble through. Thanks for your patience!


.....now if only I could figure out why I've stopped being able to post pictures,, I'd document the projects I've done,, bumper rebuild,, and doubling rear springs. :?:

micah202
06-03-2016, 07:07 PM
.

...again, not the right thread for this question,, but a continuation of sorting my cooling system.

..it's been great to continue driving with the remote thermometer just ahead of the fan clutch,, really gives me a read on what's going on. It's amazing how fast the compartment temperature rises at idle, or especially when the engine's stopped!

....:cnfsd:....A concern,,,, I might be over-worrying things, when filling the cooling system,, I run the heaters, let the thermostat open,, then top off the coolant. Most of the first time I encounter some stronger heating,, highway, heat or both,, the 2nd half of the reservoir fills up,, but never a drop more!
. I refill the cooling system as above, and exactly the same fluid goes back as came out.

Is it customary that the cooling system purges this amount?....
I'm very worried about anything that resembles signs of head gasket damage,, wondering if this is it!?


Is it possible that the times that I find the reservoir filled, I'm checking the system before it's had a chance to cool enough that the fluid is drawn back into the engine?




......an amusement....
....from a boat forum,, but makes me wonder if I'm doing the same with mah baby....

"Whazzat sound?"
"Something smells odd"
"Did that light just flicker? Why??"
"The tiller didn't feel this way 5 minutes ago..."
"Why did the bilge pump just cycle?" (ice melt running into the bilge)
I was so uptight during my first year of ownership, that I could make coffee nervous. :dizzy::roflmao:

timsrv
06-03-2016, 09:57 PM
As you already know, when you heat fluid, volume increases. When you cool it down, volume decreases. This is the reason for the recovery tank. As the engine heats up, there becomes more coolant than can fit in the system, so it overflows into the recovery tank. When the engine cools, the coolant volume decreases. When it decreases, it creates a vacuum, and that's what sucks the coolant back from the recovery tank.

In the old days we didn't worry about that. We just filled up our radiators and when the engine heated, it spit out the extra coolant on the ground. After the 1st couple heating cycles, the excess coolant was gone and the radiator stopped spitting it out (when cold it was normal for coolant level to be a couple inches below fill cap).

The advantage to the recovery tank is we can see levels without removing radiator cap, and our cars don't drip as much coolant as they used to. The down side can be a false sense of security. If there's a breach in the cooling system (can be a leaking hose or perhaps a failing head gasket), the engine might not suck the coolant from the recovery tank on cool-down. This is because vacuum is required for that to happen. If a breach prevents vacuum the system will not suck from the recovery tank. This means your radiator warning light will not illuminate, and you may run dangerously low on coolant, even though the recovery tank is full.

If you think that might be happening, check the fluid level in the coolant fill port and keep the system topped off there. If that level is always full, and the recovery tank level varies with engine temperature, then you're good (assuming it doesn't lose coolant). If there is an unexplained loss of coolant (coolant goes away but there's no signs of external leakage), then you may be having an issue with your head gasket. If that's the case, there would likely be the sweet smell of coolant present at your exhaust and perhaps some steam there. Usually head gaskets leak more when cold, but may slow down/stop when hot.

Another thing you can do is pull your spark plugs and check condition. If you have one that's super clean, then the head gasket may have a breach to that cylinder. Breaches to cylinders are a 2-way street. If you have coolant going into a cylinder, then you have combustion gasses entering your cooling system. Since combustion pressures are so much higher than cooling system pressures, depending on size of breach, it could force coolant out of your system and into the recovery tank (more than what would happen due to heat expansion). If this is happening, the recovery tank will likely overflow and you will lose engine coolant.

There are block tester kits you can purchase that detect combustion gasses in coolant. If you think this is happening I'd recommend getting one and doing the test. If it detects combustion gas, then it's time for a head gasket job. Tim

PS: We have talked about this on other threads, so for more information, search the site. Tim

micah202
06-04-2016, 06:29 PM
....thanks Tim,, a lot of information there, thanks for your effort.

That's a very useful hint to check the plugs to allay my concerns... something to do while I actually give the system a chance to prove itself! :thmbup:

petedemol
01-12-2019, 10:38 PM
Hello,

This is my first post on this forum. I have been here a bit though ever since purchasing our van a year a go.

Its a 1988 4wd Auto Tarago (thats what they are called here in Australia).

I know there have been lots of threads here addressing overheating. However, I have read most of them and performed all the recommended cures without avail. Any advice would be really appreciated. I'll lay out the details.

Issue: Overheating. Specifically under load at low speeds. Eg: labouring the engine up a steep hill with A/C on. No overheating on the freeway or at idle or if its a cool day. When I say overheating I mean the temp gauge going over half way into the 3/4 region. It definitely tends to overheat more readily when its hot outside. Its summer here so that doesn't help!

Background: I have had the van for 1 year. I love it- it does everything I want all in one car. It has never had overheating problems until recently. And I have worked it hard since having it: towing, carting heavy batteries, paddock work, etc. The problem first became evident when I was towing a trailer with some sheep to a customer (I live on a farm). It was a warm day with the ambient temp about 30 degrees celcius, I was towing approx 800kg combined weight and had the family in the car (wife and 4 children). The temperature gauge was hovering just over halfway for the outgoing trip but on the way home, when the trailer was empty, it climbed up close to the red as I slowed down from the freeway and came back into town. It never went into the red. I pulled over and the coolant boiled over. Ended up letting it cool down and refilling with water to get home. No issues getting home later that night when it was cooler. Since then it has had a tendency to overheat when the conditions are right.

What I have done:
- Replaced thermostat with a Tridon brand (from local auto store). Checked that it opens.
- Checked water pump. It is only 2 years old and spins freely and does not leak.
- Flushed and refilled coolant multiple times. The van has not really used any significant quantity of coolant during all this. Maybe 1/2 cup every 500kms or so. I find it hard to check as it seems to move in and out of the overflow bottle.
- Cleaned out radiator both inside and outside. It was clean and did not leak. Outside was grotty with grass seeds and dead locusts but is good now.
- Checked the thermofan. I wasn't sure it was working as it should so purchased a new clutch. It performed exactly the same as my old clutch (aisin) so I put the old one back in. I can kind of hear it blowing when I open the throttle at idle but I'm not totally convinced about it. I used to have a Volvo 240 and I could hear that fan come on and off really clearly from the cabin.
- I did a compression check thinking it must be a blown head gasket. 3 cyl were reading 160 psi and the 4th was 120 psi. I concluded it must be a blown head gasket causing all the trouble. I changed the headgasket and got the injectors cleaned as well. The engine runs well and the car has power but it still overheats!
- Checked Ohms resistance at the temperature sensor. It was not reading anything across the two pins and the workshop manual says it should be. However, the temperature gauge on the dash appears to be working. As in, its readings are consistent with the driving conditions and the times when it overheats. So not sure what to make of that...

I feel like I have done everything I can think of and everything recommended here by you all. I am at a bit of a loss. Any advice would be great.

I am inclined to think it is the thermostat. That is what it feels like when I am driving. It feels like maybe it should be opening earlier than it is or more completely open. It does not appear to open at all when starting the car and letting it idle. That is, the bottom radiator hose stays cold. Even when the engine is hot after a hill and I pull over and check things, the bottom hose is still never as hot as the top one.

Anyway, let me know what you think.

Many thanks in advance.

PNW vanwagon
01-12-2019, 11:35 PM
yes i've read the OEM toyota thermostat is the way to go as it's specifically made to keep the cooling system running optimally. my van's was stuck open when i first purchased and i replaced with OEM and all has been well

i've also read other posts saying their stock temp gauge was running high (3/4) which worried the owner enough to install an after market very accurate temp gauge which showed things were running at a good temperature (lower than the existing dash gauge was reading). people have said the stock temp gauge is more of an approximation

i've seen my temp gauge crawl slightly above the middle on hot days lugging up hills with the AC on but that's as far as it's gotten. hope that helps maybe others with more experience will chime in

petedemol
01-13-2019, 03:52 AM
Thanks for the reply.

I know OEM thermostats are recommended. However, its pretty involved here in Oz to get one. There are not many of these vans around anymore and the only place I could find was a Toyota service centre who said they would have to order it from Japan! It was going to take some time to get here so I decided to get aftermarket.

If the consensus is that that is the problem I guess I could still order it while Im doing other things.

I don't think the gauge is the problem as it is not "stable". It hunts around everywhere. Going down a hill or on the flat it will be where it should (3/8ths) and then uphill it will quickly climb to 5/8ths and then back again at the top. If it was just reading a little high and everything else was good then it would climb to its spot at 5/8ths and stay there.

Thanks anyway for your thoughts.

Burntboot
01-13-2019, 08:36 AM
Given all the work you have done and the fact that A/M stats are notorious for causing the exact problem you're describing, changing out the stat is the first order of business.

boogieman
01-13-2019, 09:17 AM
since its summer, you could try removing the tstat for testing purposes..

Flecker
01-13-2019, 01:02 PM
The stock TOYOTA t-stat opens at 82 degrees Celsius, and it's been refined by Toyota to work efficiently with these vans. You need to use that one... from all my research and endeavors only the OEM t-stat runs perfect.

This one: https://www.amazon.com/gp/product/B00KTKWC9S/ref=ppx_yo_dt_b_asin_title_o08__o00_s00?ie=UTF8&psc=1 (I am guessing you might not have the AMAZON option???)

Holy mother of GAWD!!! LOL Just looked at the Amazon Au site and the T-stat you need list for like $114.00!!! Here:https://www.amazon.com.au/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Genuine+Toyota+%2890916-03046%29+Thermostat+ WOW. No wonder you went after market. The cheaper aftermarket one list for $71??? What the heck is going on with the exchange rate there man? Ha.

Also, the factory gauge is notorious for not reading true. It's a fairly weak design to basically act as an idiot light at best... Lot's of peeps here have added an aftermarket digital gauge to better monitor the temp. Theres quite a few threads on it actually. The KOSO brand seems to be the go to.


Their is also the option of ADDING a piece of additional cooling equipment that I am kind of fond of, and it is outlined HERE: http://www.toyotavantech.com/forum/showthread.php?2759-Cooling-system-Mods

Hope that helped a bit MATE! :thmbup:

petedemol
01-13-2019, 02:28 PM
Ok. It seems everyone is in agreement to just get a OEM thermostat. I will contact the dealer today.

Yep, they are expensive and take a while to get here (from Japan). I will compare dealer price with amazon. Thanks for looking that up for me.
I think I paid about $30 for my A/M thermostat.

I hear what you're saying about the gauge. Funny thing is it used to be really stable before all these shenanigans. It would slowly climb up to 3/8ths and stay there no matter what the driving conditions or outside temp. So I have been going on the assumption that the gauge is fine.



I'll let you know how it goes.

Flecker
01-13-2019, 04:34 PM
Ok. It seems everyone is in agreement to just get a OEM thermostat. I will contact the dealer today.

Yep, they are expensive and take a while to get here (from Japan). I will compare dealer price with amazon. Thanks for looking that up for me.
I think I paid about $30 for my A/M thermostat.

I hear what you're saying about the gauge. Funny thing is it used to be really stable before all these shenanigans. It would slowly climb up to 3/8ths and stay there no matter what the driving conditions or outside temp. So I have been going on the assumption that the gauge is fine.



I'll let you know how it goes.


Yah, my van when I first got it ran pretty cool... never went past the quarter mark of the gauge, and upon removal I found it had failed open like most do. After I replaced it with a new Toyota one I found my gauge reading dead center and maybe slightly over at times. Kind of the normal resting spot for the temp... Heater works great (I live in snow country, just under 8,000 feet). These vans run high just due to the design of the cooling system. The Radiator doesn't exactly get the best air flow and the engine compartment heats up because it's pretty much just a closed coffin for the block/ head, all the electrical, A/C and etc... I am definitely going to have to add the remote heater core assembly up front for the summer months. Although where I live in Az, it stays around 75-80 for the bulk of the summer.

I have been to Perth and Darwin for work, I know what your guys summers are like! Ha... stay cool man!

petedemol
01-13-2019, 06:15 PM
Ok thats good to know. I just read about the heater core mod. Sounds like a worthwhile improvement.

Yeah, it can get hot here (Im near Canberra) though not as hot as Darwin! Had a few successive days of 38 degrees here. Thats your 100 degrees F.

Thank goodness for aircon!

JDM VANMAN
01-15-2019, 09:56 AM
petedemol,

Is your 88’ Tarago diesel or petrol?

I’m asking because if it’s diesel 2C series motor would it use the same T-Stat as the petrol 4Y motor?:?:

JDM

timsrv
01-15-2019, 11:31 AM
https://www.ebay.com.au/itm/GENUINE-TOYOTA-HILUX-CAMRY-COROLLA-RAV4-THERMOSTAT-PART-90916-03046/333015558379?hash=item4d894628eb:g:5UEAAOSwjDZYbt9 e:rk:7:pf:0

https://www.ebay.com.au/itm/Toyota-Tercel-1980-1998-Genuine-OEM-THERMOSTAT-90916-03046/221264090410?epid=658403643&hash=item33845e152a:g:yUcAAMXQiw5RYpQD:rk:9:pf:0

petedemol
01-16-2019, 04:22 AM
Hi vanman,

My Tarago is petrol. 4YE motor. Not sure if its the same thermostat or not but I doubt it.


Update on my overheating issues.

I have ordered an OEM thermostat as you all recommended. I ordered it from the Toyota dealer. The first guy I talked to told me $100 plus and ordering from Japan. That was when all the issues first started. When I rang again the other day I got someone else who said $35 and 2 days delivery! Very strange. Needless to say I ordered it. Coming tomorrow.

Secondly, I pulled the guts out of my old thermostat yesterday just to see how it went. I was driving around today in 42 degrees without any overheating! Awesome. Think I have finally nailed the problem. It was the thermostat all along. You guys were right. Anyway final confirmation will be when I put the OEM one in tomorrow. Will let you know how it goes.

If that ends up being the solution I will have wasted a whole lot of time and money. Very annoying. I guess not totally wasted. Learnt a lot more about the motor internals in the process.