2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

last minute opinions about replacing fan clutch

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Old Apr 10, 2004 | 09:43 PM
  #1  
Akabane's Avatar
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From: LOS ANGELES
last minute opinions about replacing fan clutch

k well my car has been overheating for sometime now and i took it to some guy who said he knew some stuff about rx7's and he said that my fan clutch was bad...
k well i don't mind replacing it but i have a few things to ask before i do replace this.

1.can the fan clutch cause too much pressure in your coolant system?
2.at 4-5rpm's is the fan suppose to be spinning the same speed as it is idle?
3.(when i push in my clutch i don't hear any noise but when it's in neutral and let go of the clutch i hear some noises like it's scratchy or something)
4.is the fan suppose to stop if you put an object in the blades with not much pressure?

i need more clues to be sure to replace this fan clutch to fix my overheating because it's gonna cost me my whole check and im cool with it..just need to be sure so i can fix the minor stuff with my next check i wouldn't want to replace a fan clutch that cost 200 bux and mines is still fine

thanks for reading!
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Old Apr 11, 2004 | 12:24 AM
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1. I don't really see how the fan could cause any type of pressure in the coolant system, as it's not connected to it in any way...

2. Ahhh, I read that the fan is supposed to go faster when the engine did, but only up to a certain point, like 4k rpm's or something, don't remember.

3. don't know what's going on there...

4. Umm, why would you do something like that??!! And umm, no, I don't think it should stop, it should break...

I think he may be right, and please don't let it overheat anymore, that's almost like instant death to a rotory. Please feel free to correct, but that was my impression...later
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Old Apr 11, 2004 | 01:13 AM
  #3  
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haha man my car almost died like 3 times it's never reached above the line hopeully it didn't hurt it too much but thanks for the reply
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Old Apr 11, 2004 | 01:59 AM
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Take out the stock fan and put a PermaCool electric fan in. Works ten times better and drastically improves the appearance of your engine bay when the shroud is removed...
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Old Apr 11, 2004 | 02:04 AM
  #5  
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When is the engine overheating? If it's overheating at idle and low speed, but is okay when at speed then it's probably the fan clutch. If it's overheating when driving at a constant speed, under load or when accelerating it's not the fan clutch.
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Old Apr 11, 2004 | 09:40 AM
  #6  
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I just put the stock clutch fan and shroud back on. Nothing seems to blow quite as well as that motha in my opinion Just cleans up the engine bay alot.
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Old Apr 13, 2004 | 05:11 PM
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Originally posted by RSOkinawa
Take out the stock fan and put a PermaCool electric fan in. Works ten times better and drastically improves the appearance of your engine bay when the shroud is removed...
How does it work ten times better?

In short, it doesn't...later
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Old Apr 13, 2004 | 05:15 PM
  #8  
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E-fan...........I say u replace the stocker.
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Old Apr 13, 2004 | 08:25 PM
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The fan clutch is rather simple and rather complicated. In a short explanation, when HOT air passes over the clutch, it starts to engauge (offer resistance so the fan begins to turn). When this happens, more air is drawn through the rad, thus removing heat. When this is done, the air is COOLER, and the fan clutch disengauges (allowing the fan to "free spin" with little power applied to the fan blades).
Sumup. When the air gets hotter, the fan spins at a closer or equal speed as the input speed (direct drive at HOT temps). When the air gets cooler, the fan slips a lot (you can stop it at idle with your hand). When this system works, it works VERY WELL, when it fails, oh snit.

Cheers
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Old Apr 14, 2004 | 11:35 AM
  #10  
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First, check the radiator:
Next time it gets hot, turn off the motor & feel the radiator fins.
If has hot & cold spots, it's blocked.
If it's not very hot anywhere, the thermostat's bad.
If the radiator is hot, the fan clutch should engage.

The fan clutch uses a silicon oil viscous fluid in two chambers inside.
The Bi-metal strip on the front bends outward as it warms and opens the valve from the reservoir side to the clutch side.
Centripetal force provides the pumping action to move the fluid.
After 100,000 miles the bearing seals wear, and the bearing lube weakens the clutch fluid's grip.
Both the S4 & S5 clutch freewheel when cold.
The s4 clutch increases it's bite gradually with temperature rise.
The s5 clutch is more on-off. (It just coasts until is gets warm)
Once they are warm, the fan speed goes up with engine speed to about 4000 RPM.
As the engine revs higher the fan stays at ~4K.
If your warmed up fan only revs up to ~2500 RPM, it's bad.
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