Electric fans and thermostats

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:

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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.

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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:

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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!!