Replacing 4Runner fan clutch with electric
 

Well, I finally decided to make the switch on my 4 Runner from the thermo fan clutch to an electric radiator fan today. Found a used Mark VIII electric fan and ordered a variable speed fan controller for it today. I went the variable speed unit since I can adjust its temp setpoint to where I want, that and I just like to control stuff. :)

I'm hoping to accomplish two goals with this change.

One, the obvious one, improve FE by reduced parasitic load.

Two, increase my engine temp a bit by increasing the radiator outlet temperature. I've checked my existing setup and found that my radiator is really over cooling the water outlet temp. On an average 95f day the outlet is about 115f now with a 180f inlet. Its also taking a long time to get my engine up to the upper 180's on the Scangauge and almost never sees 190f.

Between the two, I'm hoping for a 2 mpg improvement.

I'll post some pic's when I finish.

Most people have a lot of trouble with variable temp controllers. I would stick with a standard automotive switch. Good luck.

I'm watching your results. I too have a belt driven fan and have wondered what the FE gains would be by going with an electric fan.

While continuous control is no doubt more complicated compared to an on/off switch the benefits outweigh the increased complexity in my mind. Being able to adjust the temperature control setpoint is something I must have for this project to reach its full potential. Also its only going to run the fan as fast as required to maintain the outlet water temp at setpoint so its going to reduce amperage load spikes of the fan switching full on.
Another thing about the controller I will be using is that it will run the fan at 50% speed when the A/C compressor is running. For my application this signal input to the controller will be the compressor clutch.

I'm using a 35amp controller from here: https://www.dccontrol.com/

If it turns out to be a POS I'll be posting it here! I have seen this company's products used on other forums so its not a blind choice.;)

I run the DC Fan controller on my Jeep. Its a pretty well designed piece; easy to setup and use and its cake to wire in an on/off switch to it. Plus its survived a few dunks in water, along with sand and rock dust without blowing anything.

What temperature thermostat are you running Mentalic in the 2 Runner? If the inlet is only seeing around 180F I don't think you have a 195 degree themo installed. Switching to one of those could boost you another few points in the FE department.

FWIW my inlet temp comes in around 200-215, outlet around 130-150

On the part about towing, granted I've got a block built in the 80s, but the Mark8 fans can't move enough air when you are climbing a grade. I haven't overheated, but its gotten fairly warm.

The problem I had is I could only find stock temperature setting thermostats from even the non oem parts suppliers, and thats 82c/179.6F. I recently replaced the original stat and the new one runs the same temp as the original did or maybe a degree less... Now the Scangauge temp gets up to 190 every now and then when I come to a stop towing then drops quickly to 186F. It runs 186F on the Scangauge just about all the time after the first 10 miles, just about when I get to work its warmed up. :(

I also suspect the radiator in my 4Runner may be the same one they use for the v8 engine and I've got the v6. The radiator outlet temp has only been 115f when I have checked it. Another thing thats seems odd is that the thermostat is on the lower end of the engine and takes in the cold line from the radiator directly on top of the thermostat! Seems like on older vehicles that I actually paid attention to were set up just the opposite way.
So the thing is that since the temp control point is low on the engine may have something to do with why they run the lower temp setpoints on the thermostats?
The Mark 8 fan is a two speed unit, is that the one your using and if so which speed are you using?

Since it does take the radiator outlet water through the t-stat rather than the inlet thats probably why it has a cooler temp range. Kinda weird though since every other car or truck I've worked on has it the other way around.

Mines the 2 speed as well. I forgot exactly how I wired it, but I think I hooked the high speed wires to the controller. I can check in the morning for you if you want.

My bad. I misread your original post. I thought you were talking about a simple variable temp switch. The kind you stick between the radiator fins. I've head good things about the delta controller but never tried one. Interested to see the results. Good luck.

Reason I asked is I have seen several Tacoma install's that only use the low speed and its was plenty enough for there 3.4 v6's which is the same thing I'm running.
Hows your fan shroud fit? Does it cover the whole radiator? Just seems like it should do the job from all the postings I've read.

I've seen a video of an Mark8 van on high, its VERY loud, sounds like a light aircraft on takeoff! Don't actually have mine yet, its on the way. If you happen to take a look at your fan please note the wire colors you used. Figured Id just have to check the windings with a ohm meter then test it.

Well my Mark 8 Fan came in today. I must of had the Mark 8 and Taurus fans confused since the Mark 8 is a single speed unit. Sort of simplify the wiring issue. :)

Waiting on the Dc fan controller....


This thing moves a ton of air!
https://img509.imageshack.us/img509/232/mark8fankx1.jpg

I'm running the DC Controller on my truck, also ran it on my Tahoe. Worked flawlessly 2 years on the Tahoe, then sold it along with the electric fan package when I sold the Tahoe. So far as I know it's still working. Had the second unit on for the last year, it is showing a little green corrosion but I think that's more due to where it's installed than anything else, as the Tahoe showed no corrosion at all.

Nice thing about the DC control unit is by monitoring the radiator outlet temp, it can use the fans to control the temp of the water entering the engine after the fans have cooled the water. This means the temps won't fluxuate nearly as much as they will taking the water temp at other places like the thermostat outlet.

One thing I'd suggest (and have yet to do myself) is set the AC control wire up with an extra relay that is normally closed. Run the control tap through the torque converter lockup control wire. This way, when the TC locks up it will kill power to the DC controller's air conditioning tap, which will shut off the electric fans. If you are going fast enough to lock the TC then you are getting enough air across the condenser, and there is no need for the additional load from the fans.

The DC Control unit is an excellent piece, and I'm a hard man to please so if I'm giving it a thumbs up, it's got to be good.

Good to hear others having success with the DC Controls product. I did read a lot of good things about them before I ordered mine, just wish it was here today. Its my Friday off and I'd like to be working on this....

Thats a terrific idea to use the TQ lockup signal to interrupt the A/C fan line! I had been thinking about using a manual switch which would be better than nothing but having it automated would be the best! Time to break out the shop manual!

This is a good thread.
i like the looks of that controller :thumbup: more control IMO is great :) .
Someday I will do this to the GMC hauler.

After waiting three weeks for the DC control unit and not one email returned from there web site I was getting worried.. I finally tracked down the guy that makes them on another forum since he absolutely never replies to emails.
Seems that he's making them by hand these days and the wait is darn near forever. He's running close to two Months behind. :mad:
In the past he had a vendor making the units for him but they will only build surface mount devices now and his unit does not use surface mount components... There are lots of unhappy customers out there these days due to his lack of support and slow delivery.

So I got a refund and went with a Spal fan controler unit I've been reading good things about.
https://www.spalusa.com/

The Spal can use your existing temp gauge sensor as an input for a temperature reading but I do not want to control the fan based on engine temp. I want to control the fan based on radiator outlet temp. So I also ordered a separate temp sensor from Spal. My original plan was to tap some threads in an a aluminum pipe that extends from the top of the thermostat housing but the sensor is 3/8npt and just too darn long for that (the picture had a very short sensor tip, the actual unit is .5"). On to plan B, I'm going to cut the sensor out the brass fitting and rig a clamp on temp sensor for the same pipe.
Time to crank up the Dremel....:)

i noticed a 2-3mpg increase when i installed my efan in my s-10. got the fan for free out of a late 80's cavileer with the 2.2L and just went to autozone and got thier universal temperature switch. its just a temp probe and a variable switch. so you can control when you want the fan to be on by the turn of a dial. only costs $17 and comes with alot of wire.

Bummer, hope the guy from DC Control gets his ducks back in a row. In the meantime, I'm glad I've got mine :D.

Lucky dog, the DC control unit was an easier install too.

Its taken almost two days to rig my clamp on temp sensor, mostly due to waiting on the Marine grade silicone to dry.. Its done now. Gonna post a pic or two.

Nothing like pictures! So heres a few of my clamp on temp sensor.

Darn probe was too long to go into the pipe I wanted to install it.
https://img166.imageshack.us/img166/9876/p8171732ts1.jpg

Bit of Dremel action and I removed the temperature sensor, notice the white heat sink compound all over the sensor.
https://img508.imageshack.us/img508/4585/p8171735jk0.jpg

Made a brass clamp to fit the pipe I'm going to clamp this on and soldered on a small bit of copper tubing to hold the temperature sensor. Its a clamp on Thermo-well. The heat sink compound goes into the well then the probe then lots of the Marine 5200. That Marine 5200 dries to car tire toughness and does not come off!
https://img508.imageshack.us/img508/2...739copysx7.jpg


Its not a beauty but its going to work. I covered the whole thing with the 5200 to serve as insulation as well as too hold the wires in place. The plastic connector was sealed by wrapping electrical tape and filling with 5200.
https://img508.imageshack.us/img508/7226/p8191742yt9.jpg

Did this project ever get finished??

<--fishing for pics of installed fan/controller, also fishing for old/new FE comparision

Nope, its not complete. I ran into one tiny problem. ;) It don't fit.

I have the Spall fan controller mounted and wired up ready to go. Next I installed the electric fan into the old shroud and it was looking good. Then the next thing to do was to remove the old fan clutch. Well thats when I had a wee bit of a problem! Turns out there is a shaft that sticks out about 1" from the center of the water pump into the fan clutch. I did not have enough room to slide the new shrowd/fan assembly with that pesky shaft sticking out. :mad:

It would have fit if I removed the radiator and mounted the new fan then reinstall the radiator but thats not something I want to do every time I need to work on something... I don't like half a$$ installations..

At this point I'm looking for some sheet metal or aluminum if its rigid enough to make my own custom shroud. This way I can offset the electric fan so its not directly inline with the water pump shaft.

i assume youve done a grill block already?

you dont NEED a shroud, yes they do work, but not necessary...

pics?

Lower grill is blocked and I'm taking it out when I get the E-fan working to be sure I don't have any issues. Depending on results I may reinstall it. Most of my driving is below 50mph and I have not seen much improvement from the block I'm running.

I will not install the E-fan without a full shroud. Something has to hold it up in position anyway.

I did not take any pics of how I had it installed in the factory shroud but its not in there just now anyway. I really had to trim the E-fans shroud down a good bit for it to fit inside the factory shroud though. Used a Dremel abrasive wheel that just melts its way through the plastic easy enough.

About the only pic's I have not posted are on how I mounted the Spall controller and the manual A/C fan kill switch on the dash. Depending on how the A/C works without the E-Fan running at speed I'll try and automate it via the torque converter lock up.

What I need to do this Friday is hit the road and find some sheet metal. It really should be easy enough to make a shroud. Material and time....

lol mines being held up by part of the top shroud i cut off and a long bolt on the bottom. hasnt fallen off in about 2 years and cools perfectly fine even while im towing

You're getting 25MPG out of your 4Runner? I've got a 2000 Limited 4WD and I'm averaging 15MPG!

Yep, but mine is a 2 runner. Weighs less, fewer moving bits.

Spent a couple of hours Friday sketching out possibly building a new shroud. Turns out thats not going to work any better due the same problem, the mark 8 fan is just too deep. Mark 8 fan is 4.75 front to back and flexes about .5 inch at max rpm. Theres just not enough space from the radiator to the engine to make this puppy fit with enough clearance for air movement by the radiator.

Looking at other fan options. There's some 16" Spal's that will work. Need to decide on which way to go.

I ran two Permacool fans in a custom shroud in my 96 Tahoe, worked out pretty well. Each one is 14in in diameter, and pulls 2850CFM. Had the shroud made up out of aluminum and Rhino-lined it for sound absorption. They were very quiet and did an excellent job of cooling the 350 engine it had. The AC also worked better in traffic, since it had plenty of airflow across it at idle. I don't remember the depth though, course there was plenty of room for mine to work out. On the shroud, you only need about an inch from the radiator to the fan to get airflow across almost the entire radiator.

Finally installed the fan today, took most of the day as well. Only ran it a bit to verify operation so I don't know the FE impact just yet. I removed the lower grill block until I feel confident in this new setup.

First thing I did was test the Spal fan and controller, good thing I did. It was not calibrated at all and ran full speed at power up. The paper work indicated it was set up to work with the Spal temp sensor from the factory at 160F on, 200F high, yet mine was not.
So I had to calibrate mine, and to make it easer I removed the sensor from the truck and rigged up a hot water bath so I could set the low speed turn on at 155F and full speed at 195F. Its not had to calibrate, just get the sensor to proper temp and press the low or high button.

The original fan was 18" in a 21" cutout.
https://img341.imageshack.us/img341/5396/p7191693re6.jpg

Installed the Spal controller behind the battery tray on the fender.
https://img170.imageshack.us/img170/8417/p8191749dg3.jpg


New Spal fan mounted in stock shroud. Used some aluminum sheet and reinforced the stock mounts because they looked flimsy.
https://img120.imageshack.us/img120/6954/p9291778ex3.jpg


Front of new fan. Looks tiny but man it moves some air!.
https://img340.imageshack.us/img340/9841/p9291781cw2.jpg


Fan installed in truck. Fits with no problem.
https://img210.imageshack.us/img210/9370/p9291783aw5.jpg


Temp sensor mounted on radiator outlet line. Its wrapped with rubber tape and topped off with regular electric tape to insulate it so it picks up the temp better.
https://img210.imageshack.us/img210/1253/p9291788ev5.jpg


Top view where you can see the shaft that gave me clearance trouble with the Mark 8 fan I had originally tried to use.
https://img341.imageshack.us/img341/7833/p9291790yt4.jpg

click free...nice setup :thumbup:

click free...nice setup :thumbup:

I'm going to be adding 2 smaller fans to a 4 cyl Nissan 4x4. Only issues I see with your setup is that by shrouding the fan...you might reduce the airflow you have from just the truck moving forward...though your efficiency is increased when the fan runs.

I'm going to be using a mechanical adjustable fan switch where I put the sensor bulb (covered by silicone gasket goop) inside the coolant hose coming from the engine. I adjust these on the road by watching the temp gauge...I only want the fan to run if the gauge starts to rise above normal. This switch is on/off at one temp.

I also use a fan indicator light so I know when it is running.

I find that placing the sensor on the outside of the rad or a hose does not allow very accurate control of the fan.

My opinion is to max out the natural air flow as much as possible by not using a shroud...and be sure the fan(s) only run when really necessary. Otherwise you run the risk of spending time and $ and might be not much better off than you were mpg wise. Not using a shroud might cause overheating on the trail though.

But I haven't actually done this yet...so who knows. The fan switch I have installed in another vehicle and it works as expected....rarely runs.

Yea I realized this and its the reason I removed the front lower grill block to get more pressure on the front of the radiator. Flow is driven by differential pressure so since I now have a smaller air hole I adjusted the pressure.
Think I'm going to box in the lower section in front of the radiator to prevent it from leaking air down under the truck. Blocking this section up would be sorta like a grill block as it would reduce the air flowing through the grill, likely not as effective as the block though.

From running the truck yesterday I found out that if your moving at all I don't need to run the fan even for the A/C. I installed a switch on the dash that I use to disable the fan from automatically running when the A/C compressor is on. The plan was to switch off the fan for highway speeds but there is evidently so much air being rammed through the radiator that its just not needed unless sitting in traffic.

Trying to read the temp on the outside of a rubber radiator hose would definitely not work. Using a hand held IR thermometer the hoses read 20-50F lower than the metal they connect to. Where I'm reading the temp is metal and I'm using a flat brass clamp that gets good contact. For good measure I also applied heatsink compound for better heat transfer. Monitoring the pipe with the IR thermometer the radiator fan switches on within a couple of deg where I calibrated the Spal controller to activate. Worked better than I expected actually.

My guess on this is that you could create a kind of ram air intake for the rad that would force much air into the fan opening you have as possible...any excess would spill out over the front of the cowl and flow back?

My 300ZX had a rad that was tilted forward about 45* and had an opening above the air dam that forced air up into it. When I added an extension down from the air dam and blocked this opening...it overheated in winter. Partial vacuum?

Guess you need to go with the design...but efficiency is the name of the game.

After two days running the E-Fan the numbers don't look too good. Absolutely no noticeable FE difference under 60mph at all. At 70mph there begins to be about 1mpg advantage from my old numbers though. Since my daily drive never gets over 50mph this mod had no FE benefit on my truck.

Obviously, the Toyota thermostatically controlled fan clutch must work very efficiently. I had thought this type of result was a possibility from the start but still I had to give it a try.

That almost matches my unofficial data. At highway speeds I didn't see a change between my mechanical fan and the e-fan, under 30 I would see a +1 MPG but nothing consistent.