Defective fan clutch?

[CSquared]

As of late my car has been overheating at high speeds. I used to block test to determine that it wasnt the headgasket... We tested it cold, warm, and hot.

Anyway... My buddy jared said that it might be my fan clutch. To test this he stuck a small piece of hose(the coolant hose that runs off the top of the head to the heater control valve) in the way of the fan blades.

When the fan hit the hose a few times it stopped spinning. After it stopped spinning i was able to move the fan by hand without it trying to spin back the other way(it seemed)

So is that a sign of a bad fan clutch or would that be a normal occurance?

Regarless i am also about to replace the radiator and thermostat so that will eliminate either of those two problems.

Im just trying to find out whether or not that test was legitimate before i go and buy the fan clutch.

p.s. Anyone know how much those things go far by any chance? I decided not to go electric.

p.s.s If that test isnt legitimate... how would i go about testing it?

 

[lagged]

at high speeds you dont even need the fan to cool the engine.

if the car dosnt over heat in traffic and at idle, i would say your fan is fine.

also, maybe you should keep your buddy jared away from your car from now on! :biglaugh:

 

[CSquared]

at high speeds you dont even need the fan to cool the engine.

if the car dosnt over heat in traffic and at idle, i would say your fan is fine.

also, maybe you should keep your buddy jared away from your car from now on! :biglaugh:

haha actually he is a certified toyota mechanic and it was his head mechanic guy that suggested that method of testing.

That's why i was skeptical.

He and i replaced the headgasket about 3000 miles ago and this car has never run so beautful(aside from overheating)

So we are thinking this is the thermostat then?

symptoms:
The car won't even overheat if im cruising at 80 or 90... I really have to be beating on it for it to overheat. When it's cool out the car wont overheat... and i can beat the ever living shit out of it in stop and go traffic and speeds under 80 without it overheating.

When the car DOES overheat it hasnt gone anywhere higher than 75%... When i let off the throttle and slow down to around 60 the temp gauge will slowly return back to its normal position.

 

[Squid699]

ok...it does sound like your fan clutch is bad. You shouldn't be able to stop it by hand........BUT...like Lagged said - your car doesnt need a fan while you're driving at speed. If you're overheating while you're driving, something else is up.

 

[IJ.]

Missing undertray?

 

[figgie]

Missing undertray?

that one is sometimes needed. especially at high speeds.

 

[IJ.]

that one is sometimes needed. especially at high speeds.

What I meant was maybe he has no undertray which causes high speed overheating !

 

[CSquared]

yeah i am but i've owned and driven this car on the highway for a year without any problems.(aside from a BHG )

Those undertrays seem like a rare commodity now a days

 

[americanjebus]

try the undertray they actualy do something, hit your junkyard cus thats the only thing that seams to make sense, also whats your overlow doing, boiling? normal overflowing, and what mods do you have if any.

 

[CSquared]

I'm bone stock aside from turbo timer and arp head studs... not losing any coolant... overflow isnt gaining/losing/spilling/boiling

EDIT: oh i forget to mention that my rad is not oem. As far as i know it is just some knockoff autozone brand or something as i bought the car with this rad... Design is the slightest bit different.

Right now Im thinking either clogged rad or thermostat. I read a few other posts and it seemed like some of the other guys had problems with the thermostat after headgasket replacement. I dont know if there is any correlation between the two but it is worth a shot.

I'm just trying to isolate this problem and not replace every damn component in my cooling system.

:squint: thought the damn fan clutch was my easy solution

 

[americanjebus]

may i recomend radiator.com if your going for oem one. in the live chat thing just ask a random question thats out of place and it will be like "oh you realized that this is a computer talking and not a human heres a discount" inexpensive and realy good quality.

 

[CSquared]

may i recomend radiator.com if your going for oem one. in the live chat thing just ask a random question thats out of place and it will be like "oh you realized that this is a computer talking and not a human heres a discount" inexpensive and realy good quality.

lol i tried to talk to him and get a discount... I started explaining "problems i am having with my wife"... and he left the room.

So maybe i wasnt talking to a computer? :icon_conf

I feel like an ass now... thanks.

 

[GrimJack]

You should NOT be able to stop the fan by hand with the engine on. The simple test for the clutch is simple - just try to spin the fan by hand with the engine off - if it moves more than 1/2 turn, the clutch is toast. This test is best done with the car cold.

 

[CSquared]

but we've established that this wouldnt be the reason for my overheating right? Im just interested to know if you think differently.

 

[GrimJack]

I think differently. If your cooling system only overheats when you really push it, and one component of it is busted, fix that component and it will likely fix your problem.

 

[IJ.]

I put a brand new Delco fan clutch on during my build and man is it stiff to turn!

I'd go along with Grim change out the Clutch and also get an undertray on it mine even when it was NA would cook it's brains out at speed with no tray!

 

[lagged]

I think differently. If your cooling system only overheats when you really push it, and one component of it is busted, fix that component and it will likely fix your problem.

i agree that you should try to ensure that every component is working properly; however i really think the fan is not the problem.

if you had wired in some electric fans, they probably wouldnt even be running at high speeds. the air coming in from outside should be more than enough to cool down the engine and prevent over heating.

im thinking you should pull the rad and see how much shit has collected on it.

 

[Squid699]

the lack of an undertray will not cause highspeed overheating. I cruised for almost 3 hours on saturday at 80-100 on the highway, sans undertray and the temp didn't spike....in fact it NEVER has, cause I've NEVER had an undertray....

 

[Asterix]

Fan clutch? What fan clutch? My '88 NA has a thermal linkage thingy on the fan that looks sorta like a clutch, but isn't. As it gets hot, the goop hiding inside gets stiff. When the car is cool, I can easily turn the fan by hand.

Supra radiators love to get full of crud. That's what mine did, and it started to overheat on the highway. A new radiator took care of that. I've never had the undercover on. That's not the problem.

The service manual talks all about this.

Asterix

 

[CSquared]

Well i headed over to the local toyota dealer today and picked up a thermostat... In the process of asking one of the salesmen where the their "parts" department was, he asked me if i wanted to sell my car to him or possibly trade it in for a scion tc.. i graciously bowed out.

Anyway... so the thermstat has officially been replaced but i haven't had a chance to get on the road yet. I also picked a radiator up from a friend for $40 bucks so i'll probably do that tomorrow.(and obviously change my coolant)

If that doesnt solve my problems... it's hello Mr. cliff for my supra. You guys can visit her final resting place at the bottom.

side note: I don't know wtf thermostat was in my car but the design was different from the toyota one. Toyota one seemed like it would allow more coolant flow... Both of them opened when placed in semi-boiling water... so i am not getting my hopes up.