The Cooling System Troubleshooting thread

[VanSurfer]

Happy Day of Thanks to all of you happy TV owners!!!

So, I would like to be the first in this thread. After searching all around here and TVP, I have yet to find my problem listed. It was mentioned in this thread http://www.toyotavanpeople.com/forum...p=58889#p58889, which I just posted my scenario on.

Here's what happened. Yesterday driving down I-5, doing 65-70, just before The Grapevine, noticed that my temp had risen to about 3/4. Usually it slightly points down from center. I replaced hoses (Napa), WP (OEM), Rad Cap (Napa), and rebuilt fan clutch, about 500 miles ago since WP blew and clutch was poor,,, and OEM t-stat about 4k miles ago. Never had any overheating issues, except when WP failed. So,,, saw the van getting hot, pulled over at a station to let it cool. Checked overflow, and it was perfect. Once engine cooled enough I pulled rad cap and started engine and level was normal. Started up grapevine since temp was low. Driving 45, 1/2 way up noticed temp building again,,, so pulled into rest stop and everything was the same. No noticeable issues?!?!? Temp climbed again as I completed the rest of the climb, then dropped to normal coming down the backside. My pops lives in Venice and the temp was absolutely normal for the rest of the 2+ hour drive. Any thoughts or suggestions? It's hard to believe that a brand new Napa rad cap could be the culprit, but I'm willing to get an OEM cap if folks think that could be it.

[llamavan]

As usual, it sounds like there may be more than one problem.

First, an overflow tank that does not go down combined with coolant missing at the filler neck indicates a problem with the system between the rad cap and the coolant tank.

I'm not a believer in OEM radiator caps, at least not at this point in time; my vans are (one by one) getting Stant or NAPA and I haven't yet found a new cap that was bad (or went bad at an early age). However, others have reported this, so it would be worth replacing just to see if that gets the coolant communicating properly with the overflow tank.

The other common culprit, IME, is the hose from the filler neck to the overflow tank. I've had to replace that on a lot of vans lately. You can use bulk 5/16" hose or order OEM (which is what I do), Toyota P/N 85338-73010.


Next issue is finding the source of the actual running-too-warm problem.

From your description, I'm suspicious that it is not related to coolant loss, specifically because (1) you said you only "topped off" the coolant at the filler neck (rather than exclaiming "wow, it took a whole bunch") and (2) the van only got hot when stressed, but continued on just fine for the last part of the drive, a significant length of time, which it would not be able to do if coolant was steadily leaving the system.

With the combined symptoms of no significant coolant loss, working fan clutch and t-stat, and getting abnormally hot under stress (but not with regular driving conditions), I strongly suspect the radiator is starting to get clogged up and needs to be recored SOON. Preferably before going over any more hills.

If you have to get home and are not running with the heater on, DO turn it on if the temp starts to go up and that should help. If you are already using the heater cores, plan to give the van plenty of "rest stops" on the way, and stay alert for the cabin heat suddenly going cold (pull over IMMEDIATELY if that happens), which would indicate massive coolant loss. Then get that recore done ASAP after you get back.

Gwen

[timsrv]

Yes, and also check for debris on the front of your radiator. Sometimes you can get quite an accumulation built up there over time.

If you do get a re-core, I strongly recommend going with a custom built unit with an extra row of cooling tubes. NEC has a source in Yuba City, CA that's doing this for a very reasonable cost.

BTW, what's the story on that rebuilt clutch fan.....is it an aftermarket brand or did it come from Toyota? Tim

PS: I've been running Gates #31333 radiator caps for years and have been happy with the performance. You can get them at www.rockauto.com for about $5. Tim

[VanSurfer]

Thank you Gwen & Tim for your replies. NEC replied to my thread on TVP. He and I have talked about stuff before and has mentioned the Yuba city radiator source for the recore. I just got a radiator from Wondervan's recent '89 4wd parts van. When I get back north, I will have both tested and if either/both are bad I'm getting the recore, but if one is good I get to save some money for now. I slightly modified my original post, as I meant it to read that H2O levels were all fine, no H2O loss was observed. When I pull the rad, I'll also check for blockage on the rad or in front of it. Once again, thank you for imparting your thoughts, it makes being a new TVP owner so much more enjoyable and stress free. Hope y'all's holidaze were enjoyable.

[trestlehed]

Hey VanSurfer,

Any updates? Did you have the re-core done by Ability Radiator in Yuba City?

I'm planning on doing that in about a month. I'm also thinking about gutting the entire a/c system to free-up some airflow space in front of the radiator. Anyone else get rid of their a/c system and have good results?

Thanks,

-Mark H
San Diego, CA.

[llamavan]

I've completely removed the A/C on several vans now. Judging from the dash temp gauge alone (which is anything but sensitive, and also varies from van to van), they definitely run cooler. Maybe TOO cooler in the winter (as the operating temp falls below optimum, fuel economy also falls).

Gwen

[trestlehed]

Maybe TOO cooler in the winter (as the operating temp falls below optimum, fuel economy also falls).

Interesting. Do you think the 4 row high efficiency rad might be overkill?

[timsrv]

IMO there is no such thing as "too cool" The thermostat opens up at 185 deg F.........the rest of the time it stays shut (unless it's stuck open). Of course the heater hose circuit bypasses the thermostat, so I guess it's possible to "over cool" the engine if it's super cold out and both heaters are on high. I have never experienced that problem, but I wouldn't rule out the possibility. Tim

[llamavan]

[...] the heater hose circuit bypasses the thermostat, so I guess it's possible to "over cool" the engine if it's super cold out and both heaters are on high.

That's what I'm talking about — using the heater in the winter. I have to delay turning the heater on (the colder outside, the longer the delay) and once it's on, the operating temp doesn't climb any further. Same problem as with my 3Y van that never had A/C, except not quite as bad for the 4Y 4WD. I wouldn't call the results "over cool", just that it's sub-optimal operating temperature — a stuck-open t-stat is a WAY better example of "over cool."

YMMV, especially depending on your climate!

Gwen

[timsrv]

I don't use my rear heater. On cold days the front heater goes right to high from the moment I leave the driveway. It takes about 5-10 miles (depending on how cold it is) for the temp to reach normal. You're at a higher elevation than me though (I'm less than 300' above sea level), so I'm sure you're dealing with colder extremes. Perhaps a block heater may be in order? Tim

[trestlehed]

llamavan wrote:

The other common culprit, IME, is the hose from the filler neck to the overflow tank. I've had to replace that on a lot of vans lately. You can use bulk 5/16" hose or order OEM (which is what I do), Toyota P/N 85338-73010.

Llamavan's comments about the radiator overflow hose got me thinkin'. I cut/pulled it off. The little metal overflow tube coming out of the filler neck is totally corroded. I pushed a nail thru the metal tube to clear it and make sure that it's free to flow. I had the new rubber hose on hand so I cleaned up the tube as best I could, put some grease on it, put the new hose on and hose clamped it. This is temporary until I get a new filler neck. The old overflow hose had a bunch of rusty corroded gunk in it and no doubt it was restricting the flow of coolant. Hopefully the fillernecks are still available.
Anyone know the part # for the filler neck?
Some pics below:

[trestlehed]

Update: I drove around yesterday for a couple hours running errands. Usually I leave the cabin heater on to help cool the engine. Yesterday I didn't do that to see what would happen. When I got home parked in my garage, I popped the engine lid and guess what? No coolant coming out of the overflow tube this time. I guess my temporary fix worked. I have the new radiator filler neck & gasket on order from 1st Toyota parts.

Thanks to llamavan for pointing out that little overflow hose as a likely culprit!

My electric cooling fans never let the temp gauge go over half way. But I still intend to have the new manual temp control relays installed to get it just right as per Tim's recommendations. I will update when that happens.

P.S. I'm still having to add coolant at the filler neck. Not much, maybe a half a cup for each 20 miles I drive it. I still suspect I have a minor head gasket leak.

[gushaman]

IMO there is no such thing as "too cool" The thermostat opens up at 185 deg F.........the rest of the time it stays shut (unless it's stuck open). Of course the heater hose circuit bypasses the thermostat, so I guess it's possible to "over cool" the engine if it's super cold out and both heaters are on high. I have never experienced that problem, but I wouldn't rule out the possibility. Tim

I have experienced this on a few vans,with factory rads and a/c. its a good thing that the engine seal was gone on one so i could enjoy some warmth, because it took forever to warm up

[Lois85]

Hello! I recently replaced my thermostat because of a huge puddle of coolant under my 85 van. Probably about a year ago. The same situation just happened and seems like the same problem.
I too have a properly full overflow tank, and what look like very new hoses,, but the engine was almost to red when I pulled over.
I’m wondering what my next move is. I would like to not have to keep replacing the thermostat? I’m thinking I need a new radiator? (I’ve only had to do a couple of things to my van so far so pardon my lack of know how!)

As usual, it sounds like there may be more than one problem.

First, an overflow tank that does not go down combined with coolant missing at the filler neck indicates a problem with the system between the rad cap and the coolant tank.

I'm not a believer in OEM radiator caps, at least not at this point in time; my vans are (one by one) getting Stant or NAPA and I haven't yet found a new cap that was bad (or went bad at an early age). However, others have reported this, so it would be worth replacing just to see if that gets the coolant communicating properly with the overflow tank.

The other common culprit, IME, is the hose from the filler neck to the overflow tank. I've had to replace that on a lot of vans lately. You can use bulk 5/16" hose or order OEM (which is what I do), Toyota P/N 85338-73010.


Next issue is finding the source of the actual running-too-warm problem.

From your description, I'm suspicious that it is not related to coolant loss, specifically because (1) you said you only "topped off" the coolant at the filler neck (rather than exclaiming "wow, it took a whole bunch") and (2) the van only got hot when stressed, but continued on just fine for the last part of the drive, a significant length of time, which it would not be able to do if coolant was steadily leaving the system.

With the combined symptoms of no significant coolant loss, working fan clutch and t-stat, and getting abnormally hot under stress (but not with regular driving conditions), I strongly suspect the radiator is starting to get clogged up and needs to be recored SOON. Preferably before going over any more hills.

If you have to get home and are not running with the heater on, DO turn it on if the temp starts to go up and that should help. If you are already using the heater cores, plan to give the van plenty of "rest stops" on the way, and stay alert for the cabin heat suddenly going cold (pull over IMMEDIATELY if that happens), which would indicate massive coolant loss. Then get that recore done ASAP after you get back.

Gwen

[Flecker]

So here is what I have found, at least for me, to be an accurate list of cooling system overhaul. Total cost on my end was about $180.00 to go through the entire system and repair/ replace things as needed.

I went through the entire cooling system.

1. Hoses. Inspect them all. Any bulged, plugged or hard/ brittle ones got replaced. I prefer goodyear, gates or continental for these. Some will have to be made from a roll of bulk hose (various sizes).

2. Thermostat. New to you van? Just replace it with either a oem Toyota OR the Aisin one from Rock Auto is a great substitute. Don't forget the rubber gasket that fits around it. This item alone causes more headaches. 185* is what the open point is. They are cheap, just swap it.

3. Water Pump. Aisin is literally the best alternative here. Quality bearing and prop in these units. Paper gasket included (and yes, you will want a thin film of fipg). The pump gets weak over time, the bearing wears and pending on what the PO has run through it, or lacked in service... this parts cheap enough to just swap.

4. Fan Clutch. Aisin FCT 037. A 60 dollar part thats easy enough to test and replace. Lots of cooling issues get tracked to right here.

5. Filler neck cap. 13 lbs. Just swap it. Stant, Gates, OEM, Napa are good choices. I prefer the cap with the pressure release.

6. Heater cores. After 30 years, they get a lot of build up. Flushing may not get it clear! See Radiator comment below.

7. Radiator (and engine block/ head). This one gets overlooked ALOT and is usually inspected last for whatever reason... most likely cost related. Yank it and give it a vinegar bath! 2 days filled with white distilled vinegar and a good flush with the hose (can do the same with heater cores)! Outside of peeling the tanks and having it rodded or just a full blown replacement, this is the next best alternative! Vinegar is effective enough without being overly harsh to remove that caked on calcium and ore build up. You'd be shocked what gets flushed out with the ol' hose. And FLUSH it with the hose BOTH WAYS. The block should be flushed also. Pull the block drain plug and flush from the filler neck.

8. TUNE. These little 4y's are really susceptible to tuning! The timing and idle speed play a larger role than you would expect in how they cool. I made a 5 degree difference in temp just by adjusting to the proper timing. Adjust idle speed to normal range.

Note about the og temp gauge and sending unit.... it's 30+ years old. Trust it if you like, but validate it's accuracy at least. Mine read a bit high, only to find the sending unit was out of whack. Plus, lets face it... it's just an idiot light/ indicator. I wouldn't put lots of stock into it. Consider an upgrade to a digital read unit like so:

https://www.amazon.com/Koso-North-America-BA024R10-Temperature/dp/B07HF6XPX1/ref=sr_1_2?keywords=koso+temp+gauge&qid=1571241883 &s=automotive&sr=1-2-catcorr


Stay cool.

[bikerjosh]

Great post @Flecker. thanks

[Carbonized]

So here is what I have found, at least for me, to be an accurate list of cooling system overhaul. Total cost on my end was about $180.00 to go through the entire system and repair/ replace things as needed.

I went through the entire cooling system.

1. Hoses. Inspect them all. Any bulged, plugged or hard/ brittle ones got replaced. I prefer goodyear, gates or continental for these. Some will have to be made from a roll of bulk hose (various sizes).

2. Thermostat. New to you van? Just replace it with either a oem Toyota OR the Aisin one from Rock Auto is a great substitute. Don't forget the rubber gasket that fits around it. This item alone causes more headaches. 185* is what the open point is. They are cheap, just swap it.

3. Water Pump. Aisin is literally the best alternative here. Quality bearing and prop in these units. Paper gasket included (and yes, you will want a thin film of fipg). The pump gets weak over time, the bearing wears and pending on what the PO has run through it, or lacked in service... this parts cheap enough to just swap.

4. Fan Clutch. Aisin FCT 037. A 60 dollar part thats easy enough to test and replace. Lots of cooling issues get tracked to right here.

5. Filler neck cap. 13 lbs. Just swap it. Stant, Gates, OEM, Napa are good choices. I prefer the cap with the pressure release.

6. Heater cores. After 30 years, they get a lot of build up. Flushing may not get it clear! See Radiator comment below.

7. Radiator (and engine block/ head). This one gets overlooked ALOT and is usually inspected last for whatever reason... most likely cost related. Yank it and give it a vinegar bath! 2 days filled with white distilled vinegar and a good flush with the hose (can do the same with heater cores)! Outside of peeling the tanks and having it rodded or just a full blown replacement, this is the next best alternative! Vinegar is effective enough without being overly harsh to remove that caked on calcium and ore build up. You'd be shocked what gets flushed out with the ol' hose. And FLUSH it with the hose BOTH WAYS. The block should be flushed also. Pull the block drain plug and flush from the filler neck.

8. TUNE. These little 4y's are really susceptible to tuning! The timing and idle speed play a larger role than you would expect in how they cool. I made a 5 degree difference in temp just by adjusting to the proper timing. Adjust idle speed to normal range.

Note about the og temp gauge and sending unit.... it's 30+ years old. Trust it if you like, but validate it's accuracy at least. Mine read a bit high, only to find the sending unit was out of whack. Plus, lets face it... it's just an idiot light/ indicator. I wouldn't put lots of stock into it. Consider an upgrade to a digital read unit like so:

https://www.amazon.com/Koso-North-America-BA024R10-Temperature/dp/B07HF6XPX1/ref=sr_1_2?keywords=koso+temp+gauge&qid=1571241883 &s=automotive&sr=1-2-catcorr


Stay cool.

A little item of fairly high importance omitted, if I may:

9. Fan shroud: verify that the bottom part of the shroud is there. If not, or not sure go there https://www.toyotavantech.com/forum/...wer+fan+shroud

[Flecker]

A little item of fairly high importance omitted, if I may:

9. Fan shroud: verify that the bottom part of the shroud is there. If not, or not sure go there https://www.toyotavantech.com/forum/...wer+fan+shroud

Doh! True story!!! I take mine for granted because my van came with it intact. It does play a big role in putting the air where it needs to be.

Good catch!