if the fan clutch keeps running

[diamond777]

if it keeps running after motor is off does it need replacement????

[Dave M]

Could be.

Not easy to explain what a working fan clutch 'feels' like. Once you've had a bum one and replaced it, you'll notice the difference.

Try this. With the hood popped, but not upright (just raised above the engine bay) and the engine running (warm), you should feel considerable airflow out the sides. With the hood up and at a safe distance, you should also feel quite a bit of airflow aroud the fan shroud.

Not recommended, but if you can't tell, do the old rolled up newspaper into the fan at idle (warm). If it stops it without much effort, its not locked and likely bad. Just watch you don't jam it in there the wrong way for some quick confety, or worse ;)

[E34 530]

Can you diagnose this problem: my car will slightly overheat if I am at lets say a drive- thru or stop in front of someones house and leave the car on after I've been driving for awhile. (If I put the heat on, the needle will also go back down to dead center) As soon as I start driving again, the temp goes back to its normal position. Does this sound like a fan clutch or a faulty thermostat??

[Mewsy]

Can you diagnose this problem: my car will slightly overheat if I am at lets say a drive- thru or stop in front of someones house and leave the car on after I've been driving for awhile. (If I put the heat on, the needle will also go back down to dead center) As soon as I start driving again, the temp goes back to its normal position. Does this sound like a fan clutch or a faulty thermostat??

Mine was doing the exact same thing, changed the fan clutch and haven't had a problem since:D

[Dave M]

Can you diagnose this problem: my car will slightly overheat if I am at lets say a drive- thru or stop in front of someones house and leave the car on after I've been driving for awhile. (If I put the heat on, the needle will also go back down to dead center) As soon as I start driving again, the temp goes back to its normal position. Does this sound like a fan clutch or a faulty thermostat??


Second the fan clutch. Typical symptoms.

Dave M

[632 Regal]

does it overheat? if not then NO

[shogun]

forget about this rolled paper test, this is the BEST info I know
http://www.mwrench.com/Whitepapers/FanClutchtest.pdf

And yes, your fan clutch is done.

[Anthony (M5 in Calgary)]

I'm not sure anybody has addressed diamond's actual question. How can a fan "clutch" keep turning after the engine is off as it is driven by the engine.

[E34 530]

I'm not sure anybody has addressed diamond's actual question. How can a fan "clutch" keep turning after the engine is off as it is driven by the engine.

I think he means after he shuts the engine off it continues to "free spin" for a few rotations. At least that's what I thought of the question.

[Dave M]

I'm not sure anybody has addressed diamond's actual question. How can a fan "clutch" keep turning after the engine is off as it is driven by the engine.

Maybe took for granted that diamond understood that bum clutches are not 'locked' at operating temp and will continue to spin briefly after the engine is shut down (rather than coming to an abrupt halt with the crankshaft). This spining is not, I repeat NOT a manifestation of cold fusion or any other 'free' self sustaining energy ;)

Dave M

[Anthony (M5 in Calgary)]

Maybe took for granted that diamond understood that bum clutches are not 'locked' at operating temp and will continue to spin briefly after the engine is shut down (rather than coming to an abrupt halt with the crankshaft). This spining is not, I repeat NOT a manifestation of cold fusion or any other 'free' self sustaining energy ;)

Dave M


Could be, but even a good fan clutch will spin (freewheel) a bit when shutting down a hot engine if the clutch is between lockup hysteresis modes - so I wouldn't call it duff based on that alone.

[Dave M]

Could be, but even a good fan clutch will spin (freewheel) a bit when shutting down a hot engine if the clutch is between lockup hysteresis modes - so I wouldn't call it duff based on that alone.

It is grey, but if you can spin your fan with little effort after shut down, then it 'may' be a sign of failure. A working clutch should offer some resistance when locked.

Again, not easy to diagnose unless you've seen a bad one.

Dave M