Electric fans and thermostats

Hi all,

Last year I had a mechanic buddy replace my fan clutch with dual 9 inch electric fans by Jeggs. At the time he replaced the hose of death and the coolant water outlet plate, then fully flushed the system. The relays he bought were set to turn the fans on when the engine temp reaches 185 degrees, and turn off at 170. The stock oem Toyota thermostat opens up at 180. So the initial problem was that the thermostat was not fully open by the time the fans kicked on. So he got an aftermarket thermostat rated for 170 - 175 F (can't remember which). Everything worked great up till about 7 months ago when my expansion tank started to overflow. My engine is not overheating as the temp gauge never gets to halfway before the fans kick on and cool things down. So right now I'm guessing that the aftermarket thermostat is not opening. Here's why: A couple days ago I tried to do the exhaust gas-in-coolant test with a kit I bought at Napa.
As the engine warmed-up I had to continually suck coolant out of the filler neck with a turkey baster. After close to 15 minutes the coolant kept coming out faster and faster until I couldn't keep up with it as well as it getting too hot to handle in the turkey baster. I shut off the engine for a couple minutes then tried to do the exhaust gas test, but once again the coolant started coming up again. My test was inconclusive.

So my plan now is to remove the current thermostat (test it to see if it stuck shut or not), then put in another aftermarket one rated at 170 F and drill a 3/16th hole in the top housing as a cheap insurance policy. In addition, my mechanic buddy is looking into changing the fans on/off temps with new relays.
I was thinking new fan temps should be: fans on at 185 F and fans off at 175 - 178 F.

Another thought is that one of the previous owners may have had the head gasket replaced with an aftermarket one and as a result, some of the water jackets are blocked... Don't want to go there quite yet.

Any ideas or thoughts on all this?

Keep in mind that coolant expands as it's heated so it can be normal for it to come out of an open filler port while the engine is heating (that's what the overflow tank is for). Still, once heated the volume of coolant will remain constant...............so if it still keeps coming out that's an indication of something strange going on. Any time you are having a cooling issue it's probably a good idea to just replace the engine thermostat. I would however avoid aftermarket and use Toyota part# 90916-03046 that's set to 82c (180f). Don't forget to get a new rubber gasket (Toyota part#16325-63011).

I'm not sure what are you talking about when you say "drilling a 3/16" hole". The engineers at Toyota put a lot of thought into this so don't muck things up by drilling holes!!!

As for the electric fan t-stats, keep in mind that with the 180f t-stat normal temps at the head will be around 195f-205f. This means fans should be set to come on at around 200f-205f (head coolant temp). If you set it to shut off any lower then there's not much point in having a fan t-stat at all (fans will run all the time anyhow). I wouldn't mess around with installing a lower temp engine t-stat as these engines were designed to run with the 180f one here.

I don't know what type of fan t-stat you have, but I highly recommend one that has a sense probe immersed in coolant (the most accurate way to control fans). On my electric fan set-up I use an adjustable thermostat that has a range of around 150-230 deg f. I have it set to come on at around 205f and shut off at around 200f. It has a long capillary tube with a 1/4" probe on the end that I placed in an extra port in the cylinder head. Works great. Good luck with your problem, hopefully it's just a stuck engine t-stat. Tim

Tim,

My mechanic buddy Steve put the temp sensor in the extra port just like you described (see attached pic).
He also thinks I have a stuck (closed) thermostat based on my test the other day where the hot coolant would keep coming up out of the filler neck. He is checking with Jeggs, the electric fan maker, to see if we can get some new relays to change the fan on/off temps. If so, we'll go with the temps you suggested here.

Will let you know what I find and the proposed fix.

Thanks again for your help!

-Mark H.

That's good it's immersed, but the only way to adjust that style is to change out the temp switch (that brass part installed in your head). That brass part is a non-adjustable temp controlled on/off switch (it's preset at the factory). Your mechanic is most likely using it to trigger relay(s), but the temp at which they activate is controlled entirely by that switch. A better way to go is an adjustable type t-stat......that way you can easily change the activation temp by simply turning a dial. Once you find the sweet spot just leave it alone and you're good. IMO, that spot is when the van can run without the fan on a cold day, but when you stop for a while (engine running but no air flow through the radiator) the fan will cycle on/off to maintain a constant engine temp. Based on my experience that spot is right around 200f-205f. Here's a picture of my fan t-stat set-up. I use this t-stat to power up a 30A Bosch style relay. The relay bridges power directly from my battery to the fans. For a while I was using an ignition switched circuit, but changed to a direct battery hook-up as to avoid the "hot soak" issue. Now fans switch on/off for a while after the van is shut-off insuring quick & easy restarts on hot days. Tim

http://i8.photobucket.com/albums/a23/timsrv/t-stat.jpg

http://i8.photobucket.com/albums/a23...r/IMG_8970.jpg

Fan temp settings aside, it worries me a bit your coolant continues to be "pushed" out of the filler neck after warm-up. Usually when we see that it means combustion gasses are entering the cooling system (blown head gasket). Still, I wouldn't jump right to that conclusion without 1st investigating the condition of your engine t-stat. If you do end up doing a head-gasket you'll want to replace the engine t-stat anyhow, so it's just a good idea to try swapping that out 1st. Cross your fingers and give it another try. Good luck. Tim

Wow, I didn't know there was such a thermostat dial control. Cool!
looks like another gadget I must have!

I just found one here:

http://www.jegs.com/i/Flex-a-lite/40...oductId=751522

Thank you Tim!

Tim,

From my mechanic Steve:

Quote:

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Maybe the best thing is to work out with Tim whats best for your van and I'll install it.

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Which brand of temp switch did you use and how can I find it? The one from Jegs has only two prongs on the box and yours has three.
So if the Jegs version doesn't work I'll need to look elsewhere.

Thanks,
-Mark

Mine has the option of being normally open or normally closed (thus the 3 terminals), but for this application only the normally open terminals are needed............so I'm only using 2 of them (the ones for normally open). I'm sure the one you linked to is for normally open use only (which is what you want anyhow). In short, I think the one in your link is a good choice & a good price.

I didn't see the size of the probe listed, but it looks like 1/4". To make the transition from the 1/4" sensor to 16mm X 1.5 pitch threads (the size of the head port), I purchased a brass adaptor at the local hardware store. It originally was 3/8"mpt on one end and 1/4" compression on the other (these are readily available almost everywhere). I also purchased a 16mm X 1.5 die and simply chased the slightly larger 3/8" threads to convert to metric. The larger size 3/8 pipe thread was almost too big to chase without turning in a lathe, but with a little effort and patience this can be done by hand with only a vice and hand threading tools. After chasing, the new metric threads were perfect. Tim

I'm in the process of installing a thermostat on a van I recently bought. It had an electric fan (switched) already but I wanted to install a thermostat. I bought the 3/8ths fitting, cut metric threads and it installs fine. I also have the 1/4in compression fitting necessary to reduce it.

I noticed that I only have about 3 feet of (tube?) between the probe and the thermostat control. I was wondering where you decided to mount your control unit. I didn't see it in the pictures and you didn't talk about it.

Thanks
-Jim

Here is where I mount them:
http://i8.photobucket.com/albums/a23.../03fancont.jpg

The one in the picture is a Flex-a-Lite control box, but this is a good location (it has this same t-stat inside). If you have kids with busy feet & fingers then I'd either find another spot or cover it with some sort of box. I'm thinking about trying one of the new Flex-a-Lite control boxes that use the electronic t-stat with variable speed. The old style capillary type t-stats seem to fail every couple years. When my 1st one failed I thought it was maybe a fluke, but the 2nd one (about 2 years old now) is starting to act weird too. Of course the electronic one may not be any better, but I like the idea of it because I can mount anywhere (sensor wire can be any length). Capillary tubes are fragile too, so be careful not to bend too sharp and protect it from chaffing. I would also recommend reducing the load on the t-stat by using a relay. Tim

Update: I haven't done anything since my last post here due to my mechanic having injured his shoulder at work followed by surgery. In addition he is having knee replacement surgery in Early April and thinks he can start working on my van in mid April.

My wish list is large: fix cooling system gremlins (new T-stat, new relays for electric fans with new temp settings) and new OEM head gasket, new water pump, tps, O2 sensor. Remove rear heater and associated hoses (especially the low hanging one running crosswise under the van). New fusible link (the one under and forward of the battery tray). Possibly some new VSV's and BVSV if needed.
Fix exhaust manifold leak, check fuel injectors and clean/replace if needed. My van passed smog 2 months ago, but the tech said some codes were showing and the van was running a little rich.

Basically I want most of the hard-to-do items tackled so I won't have to deal with them in the near future.

Tim, once the work begins I'll probably have Steve my mechanic log-on as a member so I won't have to relay info to you all the time (cutting out the middle-man), if that's ok with you?

-Mark

Quote:

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Originally Posted by trestlehed

Tim, once the work begins I'll probably have Steve my mechanic log-on as a member so I won't have to relay info to you all the time (cutting out the middle-man), if that's ok with you?

-Mark

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No problem. I'd be happy to work with him. Tim

Just to help everybody get a better mental picture here is some more information on the thermostat control box I showed in my picture above. This control box is Flex-a-Lite #30332. it's really nothing special as it simply incorporates the t-stat, a couple of diodes, and a relay. I say "nothing special" because the same thing can be easily accomplished with the individual components listed above. I just like it because it keeps things clean and provides a compact/handy package........This saves time with wiring, keeps things protected, and looks professional.

I happen to have an extra control box and t-stat laying around so I took some pics:

http://i8.photobucket.com/albums/a23...m/IMG_1526.jpg

http://i8.photobucket.com/albums/a23...m/IMG_1527.jpg


Here's the Flex-a-Lite control box with the cover off sitting next to a replacement thermostat.
http://i8.photobucket.com/albums/a23...m/IMG_1523.jpg

Here's the guts. Just a thermostat, a relay, and a couple of diodes. The PC board is only an alternative for wires and it serves as a base for the spade connectors.
http://i8.photobucket.com/albums/a23...m/IMG_1524.jpg

http://i8.photobucket.com/albums/a23...m/IMG_1525.jpg

I'm also attaching a PDF of the installation instructions for anybody interested. Tim

Thanks for all the good info Tim. That controller really is simple. Isn't that the capillary type probe that you said breaks every couple years? I noticed they sell a replacement board with relay for 29$-maybe that would be the fix? Anyway, I tried to find the electronic temp probe and couldn't, I'll keep looking. I'm hoping to finally get that pusher fan in this spring-gotta love long, cold winters to keep hot engines happy:).

Yeah, my 1st thermostat lasted about 2 years (and I had it protected with a relay). I replaced it with another (the same thing). That was about 2 years ago and although it's still working it acts weird (at times it clicks on and off a lot........like for a second or less). I think it's on it's way out. Regardless, I don't trust it anymore so I'm thinking about trying their new style. I just checked Amazon and see they list all of these. Here are links to them. Tim

http://www.amazon.com/Flexalite-3033...3043290&sr=8-6

http://www.amazon.com/Flex---lite-31...3043290&sr=8-2

http://www.amazon.com/Flex---lite-31...3043290&sr=8-1

Edit:......Lol, I just read the reviews. After reading these I'm definitely going to try the #31165 unit (last link).

Awesome. Thanks again. The reviews do look good for the last one that you like. I didn't notice it saying electronic or capillary but the last reviewer said it can be converted from "probe style temp to NPT style ANYtime i want"-I'm guessing you couldn't do that with capillary type.
Any chance yours just broke due to a cheaply manufactured relay?

T-stat failed. Not sure what is failing this time around......perhaps the relay. Regardless, I decided to go with the one in the last link. I just purchased from Amazon and will post pics and a product review when I get it and install it. Tim

Quote:

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Originally Posted by timsrv

T-stat failed. Not sure what is failing this time around......perhaps the relay. Regardless, I decided to go with the one in the last link. I just purchased from Amazon and will post pics and a product review when I get it and install it. Tim

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Hi Tim,

Any update on the new relay unit? I'm getting ready to have this done soon.

I got it and installed it shortly after that post. I used it for almost a whole day before a woman driving the wrong way without a driver's license or insurance totaled my van (while it was parked). Anyhow, I plan on fixing that van but it's still "out of service"............but hey, the fan still works :yes:. Tim

Quote:

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Originally Posted by timsrv

I got it and installed it shortly after that post. I used it for almost a whole day before a woman driving the wrong way without a driver's license or insurance totaled my van (while it was parked). Anyhow, I plan on fixing that van but it's still "out of service"............but hey, the fan still works :yes:. Tim

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OMG that sucks! Glad you were not in it at the time. Reminds me of back in Dec. 2006 a guy driving home from his night shift fell asleep at the wheel of his giant Dodge utility work truck and plowed into my parked 1982 Celica (inherited from my dad/just had recent major work done to it $$). Knocked it up onto the sidewalk. Ins. Co. totaled it as it was a unibody frame and unfixable.

Good thing you have like 10 other vans to choose from!:thmbup:

Tim,

My mechanic Steve is about to do the manual temp relay installation.
Any news on the newer electronic ones.

I think the one I bought from Jeggs has the capillary tube sensor.

Thanks

My variable speed type worked flawlessly for the short time I used it. That van however has been out of commission (for other reasons) so no word on reliability/longevity. I do like the idea of electronic monitoring/triggering of the fans, and think it's going to prove to be a better system. In my experience the capillary type with the relay tend to only go a couple years before failure. Perhaps it was just a fluke, but I don't trust them anymore. Tim

PS: perhaps reading reviews on amazon or where ever these are sold might be a good idea.

hey tim, im back on the 87 4xvan, ready to put the head back on. mark the owner [ trestlehead ] wants to go with the adjustable unit shown in this thread. i havent used anything with a capillary tube since they stopped using them in expansion valves although i can install anything. is this the unit you would recommend or would an all electric unit suffice. i found a nice one at summit racing p/n 16749 mfd. by derale cooling products. i need to know so i can drill and tap the head for the appropriate sender before i put it on..... just an fyi the head is new as is the water pump and the radiator has been recored. there is currently a custom built aluminum fan shroud with two 9 inch electric fans from jegs racing. let us know what you think. thanks steve

We've talked about different things in this thread, and since I originally posted my position has changed a bit. So there's a bit of confusion & I apologize for my part in this. I was originally advocating the capillary style adjustable thermostats as I liked the performance. Unfortunately these were not very reliable & after 2 failures (each unit lasting about 2 years) & subsequent overheating, I have moved away from those. The last style I tried was the all electronic variable speed fan control made by Flex-a-Lite. Here's a link: http://www.amazon.com/Flex---lite-31...3043290&sr=8-1. This unit uses a thermistor to monitor temp (not a capillary tube). The thermistor is inserted into a 1/4" diameter stainless steel tube (closed on one end) and that fits well into a 1/4" compression fitting (shown earlier on this thread & same one I used for the capillary style). I like this unit & believe it will be more reliable, but it's a relatively new design & too soon to tell.

The one you referenced looks like it would work well too. It does however rely on the Bosch style relay. For reassurance I would probably run 2 of the relays in parallel to reduce load and to add a little redundancy to the system. Tim

Here's some pics of my Flex-a-Lite electronic variable speed fan control unit (not a capillary style). The yellow is shrink tube I put on to protect the tiny thermistor wires:

http://i8.photobucket.com/albums/a23...ps543b05e3.jpg

http://i8.photobucket.com/albums/a23...pse72d0e7f.jpg

http://i8.photobucket.com/albums/a23...ps41087d50.jpg

As always, thanks for your valuable insight and experience Tim.
Looks like we will go with the "New Fangled" version temp sender.

Hola Tim,

Novacoupe66 (Steve) is getting close to installing the new electric cooling fan relays and we are debating the on/off temps to set them at...

Timsrv wrote:

Quote:

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As for the electric fan t-stats, keep in mind that with the 180f t-stat normal temps at the head will be around 195f-205f. This means fans should be set to come on at around 200f-205f (head coolant temp). If you set it to shut off any lower then there's not much point in having a fan t-stat at all (fans will run all the time anyhow). I wouldn't mess around with installing a lower temp engine t-stat as these engines were designed to run with the 180f one here.

I don't know what type of fan t-stat you have, but I highly recommend one that has a sense probe immersed in coolant (the most accurate way to control fans). On my electric fan set-up I use an adjustable thermostat that has a range of around 150-230 deg f. I have it set to come on at around 205f and shut off at around 200f. It has a long capillary tube with a 1/4" probe on the end that I placed in an extra port in the cylinder head. Works great. Good luck with your problem, hopefully it's just a stuck engine t-stat. Tim

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I just remembered that your work van is loaded to the gills with tools and equipment, therefore requiring some heavy duty cooling capability on hotter days. My van will have the stock Toyota thermostat but it won't be carrying all that weight, and Steve just installed the now famous 4 row Yuba City radiator. He thinks letting the fans wait until 205 degrees F to turn on is too hot for the aluminum head. So the question is:
What would you recommend the on/off relays be set to with my van configured as mentioned above? (Remember it's a 4wd Auto trans). Should we just start with your above recommended settings and just play it by ear and experiment as we go?

Thanks.

Keep in mind that a van with a 180F deg thermostat & a clutch fan will run at about 195 - 205 deg F (if measured in this part of the head). This temp will display on a stock temperature gauge in about 3/8 range. If you set the t-stat to run any lower than 200 the fans will pretty much run all the time. If you want them to run all the time then just wire the fan relay direct to an ignition circuit and avoid the extra time/money of installing a t-stat. Tim

Well I don't think we want the fans running continuously. We'll go with your original on/off temps mentioned earlier in this thread and see how things work.

Thanks again!

Yeah, just play around with it until you find the sweet spot. It took me a little messing around to dial mine in. I got it set to stay off until the temp reaches the upper end of normal, then it kicks on until it reaches the middle range of normal. This way it only runs when I need it. I don't see any real benefit to the variable speed feature of mine, but it doesn't seem to be a bad thing either. Tim

http://www.amazon.com/Flex---lite-31165-Variable-Control/dp/B000CNN3LS/ref=sr_1_1?ie=UTF8&qid=1333043290&sr=8-1

how is the on/off delay behave with the later device you mention, is there a temperature range for on you can set?

It worked well for the short time I used it. That van is still out of commission though. It's the next project in cue for this winter, so I should have it back in action soon. Yes, there's a temperature adjustment for the activation, so you can set it where you like. There's more information on electric fans and fan mods in this thread: http://www.toyotavantech.com/forum/s...=1623#post1623. Towards the end of that thread I built and installed a time delay device for one of my other vans. I intend to build another and incorporate it with this controller when I get that van back from the painter. Painter says it will be done Jan 5, but not sure how long it will take me to get it back together and make the other mods I have planned. Right now it's stripped down to nothing (no glass, bumpers, dash interior, doors, nothing) so it will take me a while to build it back into a van. Tim

http://i8.photobucket.com/albums/a23...pscb2591a9.jpg

The 4x4 radiators are quite small. In addition, the front axle is also in the way. This makes it hard to fit a big enough fan to pull the proper cfs of air through to cool it under load at summer ambient temps. I have personally installed and uninstalled (due to not properly cooling) two 10 inch fans no shroud, single 12 inch w/full radiator custom shroud, and a single 14 inch no shroud that hung over a bit. The 14 worked the best, but not perfect. The single 12 with shroud was the worst.

Currently I have the factory clutch fan with a 12 inch pusher in front on an adjustable fan switch, and it cools great.

Since I generally don't give up, and since there is a noticeable power increase without the clutch fan, I am determined to make an electric fan cool better than the clutch fan.

I bought a 16 inch flex a lite syclone (not sure why they spelled it that way) a few months back. I am going to install it at an angle with the bottom close to the radiator and the top closer to the motor. Basically it will be leaning back so it clears the differential and the motor hatch cover. I will fabricate a full shroud out of sheet 0.080 aluminum.

I will try really hard to document my install and post it.

The idea of electric fans is cool (haha, pun), and the reclaimed power is great, but with the limited space it is a balancing act. Just make sure you have a very accurate and dependable temp gauge before you start experimenting.

trestlehed, did you ever get an electric fan set up and dialed in? curious as this is a job i want to do in the near future. would be nice to gain a little extra power back from the stock fan.

Quote:

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Originally Posted by mistershmi

trestlehed, did you ever get an electric fan set up and dialed in?

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Yes! It's all set-up as written in this thread. One key thing to remember is that the success of my mod
was founded on the 4 row high efficiency recore from Yuba City, CA. Then add the dual electric cooling fans, a custom stainless steel radiator shroud, adjustable relays and... Xanadu! (I prefer the Exit Stage Left double live album version). :lol:

If you cheap-out/cut corners on any part of the cooling system, prepare for disappointment.

The work on my van was completed in January 2014. So you might want to query Tim about any new developments and tech regarding temp senders/adjustable relays and such.

If I can be of any more help, let me know.

If one did decide to run the fans all the time and forgo the thermostat, there wouldn't really be any negative effect would there? I live in Hawaii so getting too cold shouldn't be an issue. Also I've been searching around and this is as good a place as any I guess to ask this: what's a good option for replacing my 89 2wd std5 crg radiator? It's seeping towards the top and bottom, and I'm not sure getting it re-cored is financially sound. Just curious to know if anyone has a go-to radiator that works well here. I might just get the one off rock-auto when I get the money.

Tim, does the thermistor in the photo you posted have threads where it inserts into the fitting? I can't really tell from the pic, but I can only find the type that isn't threaded and is designed to be inserted into the radiator.

It's a ¼" OD stainless steel probe (no threads) Here's a quote from earlier in this thread:

Quote:

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Originally Posted by timsrv

To make the transition from the 1/4" sensor to 16mm X 1.5 pitch threads (the size of the head port), I purchased a brass adaptor at the local hardware store. It originally was 3/8"mpt on one end and 1/4" compression on the other (these are readily available almost everywhere). I also purchased a 16mm X 1.5 die and simply chased the slightly larger 3/8" threads to convert to metric. The larger size 3/8 pipe thread was almost too big to chase without turning in a lathe, but with a little effort and patience this can be done by hand with only a vice and hand threading tools. After chasing, the new metric threads were perfect. Tim

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Great, thanks. I still don't understand how sliding a smooth probe into a threaded fitting wouldn't leak. As soon as I posted that, I found one.

https://www.autoanything.com/coolers...BoCbxMQAvD_BwE

It looks to me like the sensor has changed and the new one is threaded.

Hey Tim or anyone else, would you mind making a step by step instructional write up with pictures on how to install the electric fans and speed controlled thermostats. I'm currently running a 12 inch flex a lite with the fan clutch no shroud. I wanted to have something powerful enough to completely bypass the fan clutch. I know the spal has a bit more cfm but still think it would be insufficient on its own on hot days with ac or even without.. PLEASE HELP!!