Electric fan doesn't blow enough air at altitude?

[ScaldedDog]

My 88 V6 4Runner tends to overheat when wheeling in warm weather at high altitude (>8000ft), usually when doing the >2500rpm climbs we have a lot of in Colorado. It doesn't do it in Moab (4000 - 5000ft). The Flex-a-lite fan cycles fine, but it doesn't seem to blow enough air at high altitude. The radiator is only a year or two old.

Anyone else have this problem? Would some other electric fan (e.g. Taurus fan) work better? Could my flex-alite be worn out, and just not turning as fast as it used to? I've got >14 volts running to it off idle, so I don't think it's a voltage problem.

Mark

[Pazuzu]

It's not your electric fan, it's your air-fuel mixture. I don't know how high Littleton is compared to 8K feet, but if you're lower, then wheeling at higher altitude will suffocate the engine.

Now, its generally not a big issue (I took my rig regularly from home, at 2000 feet, to anywhere from 0 feet to 8000 feet and found little difference) but I'd put money on that rather than your fan.

and I was running the stocker fan on mine. Yes, you run a bit hot at higher altitudes (and lower altitudes for that matter) but it was never more than I was comfortable with.

[decyfer]

the air is a ton thinner for us in colorado. i am having heating issues at higher altitudes too. maybe cause i need a fan shroud. or maybe cause i have a big v8 that is getting thinner air thrown at it.

[OOP'S]

Originally Posted by ScaldedDog

My 88 V6 4Runner tends to overheat when wheeling in warm weather at high altitude (>8000ft), usually when doing the >2500rpm climbs we have a lot of in Colorado. It doesn't do it in Moab (4000 - 5000ft). The Flex-a-lite fan cycles fine, but it doesn't seem to blow enough air at high altitude. The radiator is only a year or two old.

Anyone else have this problem? Would some other electric fan (e.g. Taurus fan) work better? Could my flex-alite be worn out, and just not turning as fast as it used to? I've got >14 volts running to it off idle, so I don't think it's a voltage problem.

Mark

Does it have a shroud? Or is it one of those POS that you ziptie to the radiator. Shrouds work wonders when it comes to cooling.

[pr0ject42]

Mike at ORS strongly advised me to stay with the engine driven fan for durability and cooling reasons. I know you're running the 3.0, but you've got all of the goodies on it to soup it up, so this shouldn't make a noticable hit on your engine performance.

This is Paul, the guy who talked to you at ORS last week. Did you guys go on a trail run? How did it go?

[Coop 50]

The lean fuel mixture is probably the right reason for the overheating. I would think the O2 sensor and computer would correct the mixture, but it probably does it within a certain range and beyond that range you're out of luck. As Oops said, if you don't have a shroud, you should definitely get one. I have a black magic electric fan, (shroud, thermal switch and everything in one package) it never overheats. The highest I've probably been with it is Glacier Park in Montana, Going to the Sun Road, I think it is, and the truck was packed. I got a 4 cylinder carb though, cough, cough.

[2manyprojects]

On carburated engines, the higher elevation the richer the fuel mixture. I think the main reason for over heating is the engine has to work harder. The high you go, the less air = less power. To do the same thing you put your foot in it farther.

[Big One]

Here's what's probably happening, with your average carburated engine (that is normally run at low altitude) the air/fuel mixture is set fine at its normal altitude and as you climb it becomes richer which makes it run cooler and at the same time produce less horsepower and torque. This is because the air is thinner at higher altitude. The thinner air also effects the cooling, at lower elevations there is more air to absorb the heat that the engine produces than there is at higher altitudes. As you can guess from this the carburated engine usually balances out (hotter with more cooling capacity at low elevatons and colder with less cooling capacity at high elevation). With your fuel injected engine it should account for the difference in air density and adjust the air/fuel mixture accordingly which will cause it to run at the same temperature no matter what the elevation. Because the cooling capabilaties of your radiator and fan are affected by the altitude change and your engine is not is more than likely the reason that you are experencing your overheating problem. Like the members stated above, you should look into better ways to cool the engine such as installing a fan shroud, a bigger fan, or a bigger radiator.

[ScaldedDog]

I do have a shroud (it's a Flex-a-lite 165), but it's not the biggest fan in the world. Though it's a very subjective thing, I don't think it's spinning as fast as it used to, and I think that's the root of the problem. That, and all the crap (winch, etc) I've got in front of the radiator. Do Taurus fans cover more of the radiator? Are they any more powerful?

Paul, we did go on a run, to Spring Creek, Saturday. My buddy cut a sidewall and I bent my rear drive shaft, and had to drive home without it. Look's like Mike is gonna get more of my money.

Mark

[ZUK]

Originally Posted by pr0ject42

Mike at ORS strongly advised me to stay with the engine driven fan for durability and cooling reasons. I know you're running the 3.0, but you've got all of the goodies on it to soup it up, so this shouldn't make a noticable hit on your engine performance.

This is Paul, the guy who talked to you at ORS last week. Did you guys go on a trail run? How did it go?

Mike is right on.....so is OOP'S.....electric fans generally don't pull the air like the factory mechanical fan with shroud. The taurus fan is the exception but the 80 or so amps it draws is a strain on the charging system.

[Eric]

Originally Posted by ZUK

Mike is right on.....so is OOP'S.....electric fans generally don't pull the air like the factory mechanical fan with shroud. The taurus fan is the exception but the 80 or so amps it draws is a strain on the charging system.

The high speed setting only draws around 30A steady state, not 80A.

[Pat98TJ]

Originally Posted by ZUK

Mike is right on.....so is OOP'S.....electric fans generally don't pull the air like the factory mechanical fan with shroud. The taurus fan is the exception but the 80 or so amps it draws is a strain on the charging system.

Ditto...been there.