Best place to install coolant temp sensor for e-fan?

smokeyfan1000 said:

Seems to me, the extra voltage/amps required to run e fan, makes alt work harder. And we know what turns the alt.

Ever notice how the engine slows a second when you turn on your headlights? Think about it.

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uh, Alt is not working harder when the fan is off, buddy. engine driven fan is not free.
but thanks for pointing out how this new fangled 'lectricity works.
E-fan can run after engine shut down
E-fan is quiet
faster warm up
blah blah blah
deadhorse.

I'll have to find the article later, I think hot rod magazine did a clutch fan vs flex fan vs e fan on all the time dyno test. From what I got from here probably somewhere near the lower radiator hose?

Jorn said:

That's where I have mine, temperature gauge always stays steady in the middle.

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That's because you have a compensator board.

scottyd said:

That's because you have a compensator board.

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+1 After removing the comp board and using the IPD kit, I notice the temp gauge having a more sweepin range of temps. Especially due to changes in ambient temperatures

apachechef said:

uh, Alt is not working harder when the fan is off, buddy. engine driven fan is not free.
but thanks for pointing out how this new fangled 'lectricity works.
E-fan can run after engine shut down
E-fan is quiet
faster warm up
blah blah blah
deadhorse.

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Engine isn't working any harder when the engine driven fan's clutch isn't engaged . Redblock fan /Wp belts rarely/ *if ever* fail

When the efan takes a permanent vacation,(and they do) engine damage is likely to occur.

I like engine driven fan for that reason.

badvlvo said:

Then explain to me why countless OEM's use a coolant temp sensor and a fan switch separately?

You go ahead and control your radiator temp, I'll control my engine temp.

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I already explained all that.

The puzzle piece you're missing is that the fan is not and should not be responsible for controlling engine temp.

The thermostat controls the engine temp.

The fan ensures the coolant entering the engine is at a temp that is low enough that the thermostat can do its job.

Important concept.



James,

Not sure what digital fan controller you're referencing. I have a 2 speed fan, it's just 2 different windings in the motor. It's operated by a relay.

You're welcome to troll the clutch fan camp - but the other side of the coin is there are plenty cars out there with efans that would rape john's car into next tuesday, and they don't sound like UPS trucks and their AC actually blows cold in traffic thanks to being able to use the main fan to blast air through the condensor.

I'm still not sure who is seeing all of the failed electric fans. I never see them. I see lots of worn out or seized thermo clutches though.

Ive had bad fan clutches make my car overheat too. Injectors fail too, lets just carb the bastard.

Lower rad hose I guess if just one sensor.
Volvo basically doubled the size of the radiator, considerably upgraded the alternator, and controls it off the computer or cold side of the radiator, yes. I agree with this approach. 2x cooling fans might be wise, but volvo is cheap.

No UPS truck sounds really. The OE clutch is a little under-spec in size for size of the radiator and motor in the volvo. Ice cold A/C in traffic on a hot day. Pusher (I use a Toyota pusher fan and relay), rarely comes on on the A/C high side switch. 100F idling in traffic. Fuel efficient generally. In normal driving, locked up fully sitting idling, unlocks quickly on takeoff.

Dynoing a car and loading it over time, the hydraulic drive fan drew a few HP to keep the engine at t-stat temp. Car has extremely cramped inlet and radiator, largish engine. Simulation of towing on hot day with A/C on.

Running the OE e-fan stuff with 2x bigger radiator in good repair resulted in several stops and near catastrophic overheats.
Trucks and heavy equip that don't have need for like a 6hp alternator or giant electrical system (LOL) always have a clutch of hydraulic drive cooling fan. Locomotives have electric cooling fans, but they also are electric motor drive.

Do what you want. Most cars with big power that have electric cooling fans have a giant alternator, good fan control, and more than one fan with a GIANT radiator, especially if rated to tow. Additional electrical fail safe might be a nice touch.

I know how the "2 speed" fan motor works. Much like a wiper motor or various others...2 sets of windings. Variable speed control is nice. *shrug* I am only posting this, as I think saying "this has no compromise" and is "the same" for all uses for control and performance, isn't always true. I think we mostly agree. I'm not trying to cram my experience and findings down everyone's throat, but if you want it to last and work in all conditions, add some fail safes and precautions.

945ti said:

Lower rad hose I guess if just one sensor.
Volvo basically doubled the size of the radiator, considerably upgraded the alternator, and controls it off the computer or cold side of the radiator, yes. I agree with this approach.

No UPS truck sounds really. The OE clutch is a little under-spec in size for size of the radiator and motor.
Dynoing a car and loading it over time, the hydraulic drive fan drew several HP to keep the engine at t-stat temp.

Running the OE e-fan stuff with 2x bigger radiator in good repair resulted in several stops and near catastrophic overheats.
Trucks and heavy equip that don't have need for like a 6hp alternator or giant electrical system (LOL) always have a clutch of hydraulic drive cooling fan. Locomotives have electric cooling fans, but they also are electric motor drive.

Do what you want. Most cars with big power that have electric cooling fans have a giant alternator, good fan control, and more than one fan with a GIANT radiator. Additional electrical fail safe might be a nice touch.

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Most heavy equipment is diesel. Significantly different requirements. Not a valid comparison. Half the time the issue with diesel stuff is actually keeping it warm, not the other way around.

Dynos can mask or magnify cooling issues depending on the dyno. I managed to make 540whp with a broken water pump on the dyno. We used a chiller and the pulls were short.

That said, with a functioning water pump I had no cooling issues at 540whp using a standard 2 speed efan from a V70 and a standard size Nissens HD rad.

I could flog it on the dyno at 24psi as much as I wanted.

And towing over hills with the A/C on on a warm day, I definitely found the e-fan and new 940T radiator (about 2x the size of a 240 radiator), to be lacking. This is a stock car really. Not exceeding the towing/loading capacity. Not an ill maintained car. 85+ out, constant boost for long periods, high elevation, and A/C on...by the time the air even gets to the radiator (thru A/C and IC), it is probably close to 150F? Now you are trying to exchange heat to keep the engine at 180F? Lulz. It's really not that hard to imagine or picture, is it?

I know keeping warm is important on trucks/others. But not always. Depends on the day/work load and application.

Hydraulic drive fan was on a gasoline car. 600 something hp. Driver.

Why would a person dyno a car with a broken water pump? I would imagine water not circulating as it should is not especially good for big long aluminum head engine? Or does the "chiller" pump the water?

At least we can agree about basic control, and using a hooptie e-fan with ancient 55a alternator might be unwise? I think?

Captain Bondo said:

I already explained all that.

The puzzle piece you're missing is that the fan is not and should not be responsible for controlling engine temp.

The thermostat controls the engine temp.

The fan ensures the coolant entering the engine is at a temp that is low enough that the thermostat can do its job.

Important concept.
.

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What controls your engine temp when the thermostat is open? The radiator and fan.
Once you reach the temp where the thermostat is open you rely on the fan and radiator to control engine temperature.

So it is and should be responsible, in part, for controlling engine temp.

In hot climates conditions are encountered where the thermostat is open all the time and only the fan can keep it cool.

Ever since VW went fwd with a sideways motor in the '74/5 Golf/Rabbit -- electric cooling fan use has been on the rise. Dramatically on the rise. Eventually, almost every OEM out there had moved away from a mechanically driven fan regardless of the drivetrain configuration. HUNDREDS of millions of cars/trucks over the last 40 years have been produced with electric cooling fans. It's hard to buy a new car that DOESN'T have an electric cooling fan(s). They're almost always quieter than mechanicals, more efficient, offer packaging advantages and they move the most air when you need the most air moved (opposite of a fan that turns at engine speed). Properly designed, the fans and control systems are every bit as reliable as mechanically driven fans. Doesn't mean the fan or the control system is foolproof - but they are clearly a better mousetrap. ASSUMING the fan choice, control system and alternator choice is properly spec'd/designed to work together.

The move to electric accessories and hybrid drivetrains has resulted in reliable electric-run accessories of almost every type - power steering, power brakes, a/c compressors. At the end of the day - they're electric motors and properly designed/selected electric motors are pretty danged reliable. And they're being used more and more by the OEM's primarily because of the efficiency gains as the OEM's try and hit increasingly tough gas mileage targets. The OEM's usually get it right - especially over a bit of time. Most of the problems people experience with RETROFITTED electric fans/control systems occur because a compromise occurred when selecting their parts (poor quality, trying to keep costs low, used parts, etc.) or didn't know what they were doing with installation. And when something fails the story that often gets told is 'electric cooling fans are unreliable because mine failed.'

In terms of the OP's question - the ebay description says the sensor opens at 170F and closes at 180F. What's the stock t'stat temp in the 93 - probably 87C/188F? If you put the switch on the output side of the t'stat (housing, hose, rad hot side) then the fan is going to run all the time once the car is up to temp. You may get around that with an 82C t'stat - but typically you want a good 5-10F delta between the t'stat temp and the temp at which the switch opens (turns the fan off) to keep the fan from running all the time. So I'd say if you run an 87C t'stat and your switch location is on the hot side of the coolant tract, what you need is a switch that turns the fan on around 195F and turns it off around 205F. If you're going to run an 82C t'stat - then a 180F/190F switch in that location should do. You're going to have to play with switch temps if you choose to sense on the cool side of the radiator. There are other things I find troubling about this fan. ANY electric fan/control system that sells for $50 is going to be a piece of crap. No way to put that gently. Also - it says you can reverse polarity and make it a pusher as well as a puller. That means that fan blade design is compromised - which means it will be neither as quiet or efficient as it could be. The 2500 CFM rating means nothing without some idea of what resistance it was pulling against. If indeed it's only pulling 10-20 amps, it's not going to move much air. So I wouldn't be surprised if it's not up to the task of keeping this car cool. Just a gut reaction -- you usually get what you pay for. I'd rather go with a junkyard fan off of a car with a similar/larger engine than with this $50 china-bay special.

Bondo/badvlvo - if the system is set up properly - the t'stat controls engine temp when the fan isn't on (warm up, steady cruise above 30-40 mph); once the fan comes on (on a properly controlled system where the fan isn't running all the time), the fan control system will control temps. For a switched system it will be the open/close temps of the switch. For a variable speed/current controlled system it will be the set point of the fan -- which should be 7-10F above the t'stat temp to keep the fan from trying to run all the time.

Mine has a 180F t'stat and variable speed controller set at 187F. Once warmed up and at cruise it runs in the 178-182F range. Once I slow enough to not have sufficient airflow across the rad to reject enough heat, temps climb above 185F, the t'stat is all the way open and the fan controller is controlling at 187F. My temp gauge is reading just right 190F under these conditions. I haven't had the temps vary from that -- it simply takes longer for the fan to come on/or they come on at lower road speeds when ambient temps are colder. When ambient temps are hotter, they come on more quickly at idle, run at higher speeds and I have to hit higher cruise speeds before they go off. Summer in the south (90-100F) I have to be at 40 mph for a good 30-60 seconds before the fans start to slow down and cycle off. Winter (25-50F) it's not uncommon for me to sit at a light for 30 seconds and still not have the fans come on at all. I can see it all happening on a gauge we configured to show relative fan speeds -- a fan 'tach' if you will.

Coolant temp goes up after shutdown, it's nice to have a fan sender up top that can run at any time.

Captain Bondo said:

Always in the lower hose (outlet). You don't switch the fan on because the coolant entering the rad is hot. Of course it's hot, it just came out of the cylinder head. You switch the fan on when the coolant leaving the rad (entering the motor) starts to get too hot. That means you need to increase airflow through the rad.

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This ^

Plus that way if you are running low on coolant you don't uncover your sensor and keep your fan from turning on (ask me how I know).

I advocated keeping and rebuilding the hydraulic drive fan on supra/soarer over electric. How much air it would move at redline on the electronic control "high" setting was far greater than any electric fan ever will without an alternator the size of a jet engine and welding cables to the motor.

Given that the interior heater fan draws over 15amps, don't expect miracles from some china 50 dolla special that claims numbers in the sky all at 15 amps on a small 240 radiator and alt...it might be just fine cool weather no ac. A/c blowing freezing cold climbing while towing on a turbo model...or worse...turbo automatic...expect to find some interesting things tearing it down 3 times at low boost even with the head breathing better than stock/dinky mitsu turbo (that results in a really big mess continuous boost with all that heat backed up and disaster for ebr).

Most heavier/towing friendly big power cars and trucks have a clutch or hydraulic drive fan. Those faster cars that are electric fan usually had a giant alt, 2 fans, GIANT radiator with plenty of frontal area, temp switch or sensor in bottom of radiator cold side (Toyota )...and I think that's just fine too.

The tbrix way: temp switch on hot hose (facepalm), efan from some lightweight/utterly disposable car wih hooptie na engine, on stock ancient wiring and 55a alt, small radiator with turbo stuck on the side of tired b230f I doubt you guys tow over long passes in the heat or have working cold a/c by in large, so uh...I guess that avoids/postpones certain death...slightly

Have a good idea of what each component must do...Tstat mostly regulating temp (ecu control a few degrees higher for turn on) and/or radiator cold side switch, radiator and fan and alt appropriately sized for use and application.

If need be I'll end up with a Ford fan if this one is weak. I'm not a complete idiot; I won't let the car overheat.

I didn't mean for this thread to become a pissing match and war; I asked a legitimate question, I was trying to get as much load off of the engine as possible to make it a little peppier, it's not a tow rig or anything like some people think it's going to be. (I don't think I ever even said anything about towing?)

Captain Bondo said:

I already explained all that.

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And you've explained it quite well. Some people just don't hear.

Captain Bondo said:

I'm still not sure who is seeing all of the failed electric fans. I never see them. I see lots of worn out or seized thermo clutches though.

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I've had electric fans fail several times, twice because of failing aftermarket controllers and once from a fried connector on a 1,000 mile trip. Luckily, no engine damage. It's a risk you take. If you're one who never pays attention to gauges, probably better to have a fan clutch.

All the bad fan clutches I've seen failed in lock-up mode, so they made a lot of noise, but were no threat to the motor.
Dave B

Fan clutch failure modes are varied. I've seen some that freewheel forever, some that are very on/off, some stuck on. Brand new? Not overly loud, progressive lockup, takes whatever is thrown at it. It is under spec for the motor, and life varies a bit. Mostly longer then 100-200k?

The one on the 1.6l Toyota is much longer lived and like 2x as heavy duty as the Volvo one LOL. Crappy radiator without much frontal area tho. 2.4 Toyota one...giant and quiet, much longer lived, failure symptom usually a little lazy idling wih a/c on in the hot. Similar rotational speeds...bit slower on the 1.6, about the same on the 2.4. B230ft/small water pump pulley obviously faster tho...I never ran that one for long if the car was to be wound up much, unless you like replacing heater cores 3-4x

Quick run through of all the cars I've owned since '78 (my first new car purchase) -- I think 4 had mechanical fans - '69 Mercury Comet (urban gorilla transport in Houston), a '76 242, an '89 Bronco II and a '94 Explorer. I replaced the mechanical fan on the 242 with an electric because the mechanical wasn't quite getting the job done in Houston in August with A/C on el maximo sitting on I-10 for half an hour at a time during rush hour. Thermal clutch on the Bronco II failed (also Houston) and I replaced with an electric based on how well the electric worked on the 242. 21 different cars during that time including the 4 above - never a fan or connector/controller/switch failure, never an alternator failure and never an overheat - although I worried about the 242 a couple of times before I put the electric on. For completeness - there were also 4 liquid cooled motorcycles with electric fans - no failures there; one air cooled 911; and one liquid cooled SCCA racer ('74 Corolla) with no fan at all - except for the heater fan which ran on high the whole time I was racing in TX during the summer. Something on the order of a million miles over that time.

edit - memory slow to coalesce - over 7 years of racing I towed the racer with the Bronco II, about half of that time with the mechanical fan; the other half the electric. 95% of that in TX from Mar. through October. No difference in cooling performance at all that I recall between the mechanical and the electric. Just much quieter with the electric.