Clutch fan.....good or bad?

[Mudweiserjeep]

Did a search...couldn't find.

How do you check the fan clutch? How do you know if it is bad?

 

[Shorty]

with engine off and cold check for any play in the bearing first. If it passes muster, turn the fan and check for resistance- it should turn fairly easily cold.
As the engine heats up, the fluid coupling in the clutch will increase resistance until it's much more difficult to turn the fan. If it's too tight cold, you're wasting energy turning a fan that you don't need and if it's too loose hot, you're not moving enough air at low speed to cool the engine.

--Shorty

 

[tgregg]

I just did a whole string a couple of weeks ago on this topic. The bottom line was you really can't test them. The advice to me was replace the fan clutch every 5 years. I'm in the middle of doing that right now.....waiting on parts.

 

[92DripCherokee]

Theres 3 tests, none foolproof. Ive had an otheriwise good fan clutch that locked up too soon and prevented warmup.

1) Grab opposite blades by hand, and rack the fan in all directions, it should have zero play up/down/right/left/in/out.

2) When fully warmed up, stop the engine. Before things cool down much, try to spin the blades, the more resistance to turning you feel, the better.

3) Look for leakage, or staining around the fan clutch shaft. The silicone will leave traces if its leaking out

 

[Israel]

I just did a whole string a couple of weeks ago on this topic. The bottom line was you really can't test them. The advice to me was replace the fan clutch every 5 years. I'm in the middle of doing that right now.....waiting on parts.

x2. I replaced the thermostat, water pump, and radiator trying to chase down the cause of the overheating on my ZJ. The fan clutch looked fine, didn't have any play in the bearing and was harder to turn when the motor was up to operating temperature so I didn't even consider it. A buddy at work told me his dad's truck had the exact same overheating symptoms as mine (slow increase in temperature on the freeway especially going up gradual hills) and a new fan clutch cured it. I figured I had replaced damn near everything else so it was worth a shot. New fan clutch and BINGO! No more overheating.

 

[Mudweiserjeep]

Thanks for all the input. Mine is toast. It seems to be seazed up all the time. Very hard to turn cold and is the same hot. Guess I will be looking for a new one. Jeep has 260K plus........prolly never been changed.

 

[whatevah]

mine was a little more obvious, it fell apart. lol well, it started wobbling first, then all of the internals came out and had no control over the pitch of the fan blade... wedge it into the bottom of the radiator frame and against the alternator. yeah... fun. had to use a pry bar to bend it out of the radiator. luckily, it didn't puncture anything. luckier still, it happened in March and wasn't warm enough to overheat without it, I drove it for two days until I could find a new clutch, fan, and shroud.

 

[Mudweiserjeep]

mine was a little more obvious, it fell apart. lol well, it started wobbling first, then all of the internals came out and had no control over the pitch of the fan blade... wedge it into the bottom of the radiator frame and against the alternator. yeah... fun. had to use a pry bar to bend it out of the radiator. luckily, it didn't puncture anything. luckier still, it happened in March and wasn't warm enough to overheat without it, I drove it for two days until I could find a new clutch, fan, and shroud.

wow....need to get mine replaced....don't need any of that fun.

 

[RichP]

The technical FSM method involves a thermometer and a drill. You drill a hole in the fan shroud. Stick thermometer on and start engine, let it warm up, as the fan clutch cycles you will see the thermometer go up and down as air flows over the bulb. Exercise care here and don't hit the fan.
Rule of thumb, start engine cold, the fan should 'roar' for about 30 seconds until the fluid inside gets redistributed in the clutch at which point it will decrease in sound. Your fan probably stays at a steady roar.
There are more than a few people here that would probably buy that seized fan clutch here on the site. Some will drill holes and pin the clutch closed or go buy spacers and remove the clutch completely.