Fan Clutch

Clamp the body in a vice. Clamp a vice grip round the spindle after protecting the thread. Playing a hot air paint stripper gun over the spring area. At somewhere around 100C it will start to lock. They only lock up under pretty arduous conditions.

Word of warning - I had a broken and a missing blade on my E30. Didn't seem to affect the cooling, so I didn't worry.

One day, another blade broke off and broke the radiator top hose mounting resulting in a lot of steam, a new rad and a new fan.

When the old fan was removed it fell to pieces.

I suggest you replace the fan ASAP and save yourself the pain of replacing whatever a flying blade breaks on it's bid for freedom :-)

Al.

Will it _ever_ lock when, at idle, the fan actually spins backwards?

Not only does the fan sit stationary during times that the engine is at idle, but the fan actually pulsates in the opposite direction that it should be driven in.

I am willing to replace the fan clutch, I just need a good price. I'm having trouble finding the fan itself, but the clutch is available for 90-ish dollars.

It will only lock when the the clock spring is at a high enough temperature. And that's usually only at low speeds - as at higher ones the natural airflow prevents this. But all the ones I've had transmit some energy to the fan - I can't see how it would run backwards. But of course it could be just faulty - although all the ones I've had fail have failed locked.

Weird. Even if the electric fans were running I'd expect that airflow to make the normal fan turn in the usual direction.

Can't help there, I'm afraid.

Correct operation

The fan has a thermal coupling - it only spins when the car is hot and IIRC also only up to about 2k5 rpm.

If the engine gets too warm the electric fan will be switched on. I suppose this might blow the fan around retrograde, but unlikely.

Replace the fan - it will be out of balance - also why or how did this happen? Tools dropped in the engine compartment.

Only replace the clutch if it is going to be a lot easier and not very more expensive to replace both. A breaker might well have this part, although of course most BMW's end up there through front end damage.

I have never seen a fan sit stationary, much less pulsate in the reverse direction. I'm sure the fan clutch is completely toasted, else the fan would at least spin after it is stopped from moving by resting a finger on the edge of the blades as they whirl past ...

The car idled for about 20 minutes while the fan sat in one place, and the temp guage was at mid-scale. One would think that without the fan working, the temp would rise beyond the mid point while the car was parked in the garage and running for 20 minutes.

There is generally enough drag on the viscous coupler to cause the fan to spin all of the time. I've stopped many a fan from spinning while the motor runs at idle, and the fan always starts to spin again when I let it go. This fan not only can be stopped, but when left alone after it has been stopped, it remains stopped.

Unknown. My guess is that somebody that worked on the car for the previous owner must have left a tool too near the fan.

"Jeff Strickland" wrote

Pete

Excellent resource. Thanks,