LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Bad fan clutch?

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Old 01-27-10, 05:02 AM
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deanbrown
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Default Bad fan clutch?

Greetings,

Sounds like the main cooling fan is always spinning round like crazy, matching the engine speed. Very noisy. Is this a bad/stuck-on fan clutch? I assume my options are just replacement?

Any good sources for parts I could look into?

Many thanks

-Dean
Old 01-27-10, 07:00 AM
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python
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spin the fan first thing before the car is started, if it spins more than 4 or 5 times its bad, also a bad fan clutch will cause poor a/c performance as well.
Old 01-27-10, 07:49 AM
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ck90211
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I just replaced the fan clutch and the bearing base yesterday. Hit a big pot hole the day before, and fan started to make clicking noise. Follow Python's advice, and clutch is about $55 parts at Autozone (with commercial discount). Quick to change but you will have to remove drive belt. If you are hearing noises than it might a bad bearing (which costs $135 commercial).
Old 01-27-10, 08:06 AM
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Li Ls4
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just changed mine also this past weekend, simple swap, did it without removing the drive belt
Old 01-27-10, 03:01 PM
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LiCelsior
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i have one off a 92 LS, $40 shipped.
Old 01-27-10, 07:20 PM
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deanbrown
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Originally Posted by python
spin the fan first thing before the car is started, if it spins more than 4 or 5 times its bad, also a bad fan clutch will cause poor a/c performance as well.
Thanks for the tip, but I don't understand: If it spins too much, isn't it too loose? To me it sounds like it is stuck on (too tight).
Old 01-28-10, 09:47 AM
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3UZFTE
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Originally Posted by deanbrown3
Thanks for the tip, but I don't understand: If it spins too much, isn't it too loose? To me it sounds like it is stuck on (too tight).
No, you would think that would be the case, but the resistance in the clutch causes the fan not to spin as fast as the motor as the silicone takes some resistance causing the fan not to spin as much. Once the engine heats up and gets hotter, so does the silicone in the clutch, causing the fan to spin faster and faster due to less resistance, thus matching the engine's speed. What Python is trying to have you test is to see if the silicone in the clutch is still good or has worn out. If the fluid clutch is worn out, it will spin >4 times around on a cold engine, if it is good, it should spin <2 times around. Make sense? If you have ever driven a truck or sports car with a fixed fan, it sounds like a prop engine when it's warming up trying to push the fan through the air at lower speeds, it's pretty annoying. Some have bypassed the clutch itself, and ran an e-fan.

Last edited by 3UZFTE; 01-28-10 at 09:50 AM.
Old 04-15-10, 08:10 AM
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deanbrown
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So, back to this car for a change from my land rover, I checked the fan this morning when the engine was cold, and it is not spinning freely at all - in fact if I turn the fan blades, the whole unit slips on the drive belt (if I turn it with enough force, that is). I'm not familiar with the inner workings of the fan, can someone tell me which part could be broken? Looks like the fan will spin at the same speed as the engine now, as it's stuck hard on the crank shaft.

Sounding like an airplane gets old after a few months.
Old 04-15-10, 08:22 AM
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Li Ls4
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its the fan clutch. hit up LiCelsior i think he still has 1 laying around
Old 04-15-10, 09:13 AM
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deanbrown
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Thanks - but I just ordered one from my local autozone - $54 by tomorrow, not bad! Part #922656.
Old 04-20-10, 01:08 PM
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deanbrown
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Well, to follow up, the autozone clutch is very simple to install - around 1/2 hour from start to finished. I undid the 4 bolts attaching it to the mount, and pulled it out complete with the fan attached. No need to remove the fan shroud.

Nice and quiet now, too (after 6 months of driving an airplane)
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