My '89 XJ starts to overheat when idle or running at low speeds, after doing some searching it seems the most likely problem is the fan clutch. How difficult is it to replace? Anyone know of any guides online? Also when I went to look at an online parts store I notice they had two types listed, thermal and non-thermal, what's the difference? Thanks in advance.
The job isn't too hard. There are 4 nuts on it that need two wrenches to get off or a strap wrench. I hold the clutch with a wrench on one nut while breaking the others loose, then if I can't jam a screwdriver across to hold it, I let one of the last broken free ones tighten back up as I use it to brace for the last stuck on one. Once the last one is broken free, the one just tightened come off easy.
You should test it first. If you get the engine nice and hot and have someone shut it down while you watch, a good fan clutch will stop the fan almost instantly.
There are two major types of clutches! One is the reverse rotation one your serpentine belt needs and the other is a normal rotation one for a V belt engine.
I am not sure what the thermal or non thermal means. The clutch is activated by heat, so...
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sKy>
Thermal is based on the temp through the radiator blowing on a coil the hotter the more clutch. Non-thermal uses a liquid in the clutch hub but does the same thing. There is a big nut behind the clutch rightly tight lefty loosey, remove fan blade reinstall on new assembly reinstall on shaft.
It's easy. Sorta.
You have a fan shroud that makes life difficult while working on the fan clutch, but all you need to is lossen the respective belts and you can take the fan clutch off and put the new one on.
Thermal and non-thermal? I haven't heard of that before, but a silly wild ass guess, (SWAG in short) is that the non-thermal will have a viscous material that keeps the fan moving pretty much all of the time, and the thermal will have a lock-up mechanism that is heat activated.
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