Cooling fan fell off and cooling fan clutch - The Unofficial BMW M5 Messageboard (m5board.com)

HDClown · 14th June 2009, 03:23

I came home and pulled in the garage and heard an unusual noise from the motor. I got out with the car running and radiator cooling fan wasn't spinning, something wrong there. It's 90F out and it should be spinning. Shut off the car and discover:

Fortunately, the fan landed perfectly between the radiator and the shroud. Zero damage to the radiator fins, cooling hoses, or intake plumbing, YAY. The threads are fine and I was able to thread the fan back on fine. So it had just come loose.

I unthreaded the fan and pulled it out to check on the fan clutch, as I know thiese are known to seize up on higher mileage cars. I can free spin the clutch in both directions, but it seems tight to me. I'm not sure if this is normal or not. Should it require a little bit of force to move, or should it be very free spinning? Car only has 64k miles.

The clutch itself is $160 and I have an order into Tischer already waiting to be shipped due to some backorder items. So I think I may just play it safe and add a new clutch to the order. $160 would be well spend if the clutch seizes and the fan causes radiator and cooling hose carnage from "exploding".

Hdhntr23 · 14th June 2009, 03:30

Quote:

Originally Posted by HDClown

I came home and pulled in the garage and heard an unusual noise from the motor. I got out with the car running and radiator cooling fan wasn't spinning, something wrong there. It's 90F out and it should be spinning. Shut off the car and discover:

Fortunately, the fan landed perfectly between the radiator and the shroud. Zero damage to the radiator fins, cooling hoses, or intake plumbiny, YAY. The threads are fine and I was able to thread the fan back on fine. So it had just come loose.

I unthreaded the fan and pulled it out to check on the fan clutch, as I know thiese are known to seize up on higher mileage cars. I can free spin the clutch in both directions, but it seems tight to me. I'm not sure if this is normal or not. Should it require a little bit of force to move, or should it be very free spinning? Car only has 64k miles.

The clutch itself is $160 and I have an order into Tischer already waiting to be shipped due to some backorder items. So I think I may just play it safe and add a new clutch to the order. $160 would be well spend if the clutch seizes and the fan causes radiator and cooling hose carnage from "exploding".

That is one of my nightmares. The clutch siezing at speed and it shooting thru my hood and motor.

Glad to see that you were lucky and it fell without damage.

Lawaia · 14th June 2009, 04:53

The clutch fan should spin with a bit of resistance, and will fluctuate based on temperature. Did you have the fan removed recently?

HDClown · 14th June 2009, 05:08

Fan shouldn't have been removed for any work I've ever had done on the car since I purchased it 4 years ago. Based on prior service history to that, I can't see anything that would have required the fan to be removed.

HDClown · 14th June 2009, 18:06

Thought about work done on the car last night and remembered the starter was replaced, would the fan have been removed for that job?

chowdah · 16th June 2009, 04:55

Engine fan fallen off

HDClown · 11th July 2009, 20:10

I've got a new fan clutch now and installed it back into the fan blades.

In terms of properly securing the fan clutch nut to the water pump, is jamming the pulley/having a special tool so it doesn't spring the only safe way to secure it? I've got it on right now just using a wrench and my body weight as well as a rubber mallet, but since the pully springs, I don't reallly know how tight it's on there.

nightkrawler · 12th July 2009, 16:36

its probably toast at 60k. easy way to test these, get a newspaper and roll it up. make sure the engine is cold, like first start of the day. with the engine idling try to stop the fan from spinning with the newspaper. it should take very little effort to stop it, if it dosent stop easily then its shot. fan clutches locking prematurely im sure is another reason why some of these cars run too cool.

HDClown · 12th July 2009, 22:46

I already replaced the fan clutch, question was in regards to re-securing the fan clutch nut onto the water pump. Some additional research indicates that spinning it on hand tight until it stops is adequate, and it will self tighten itself as it runs. I actually tightened down with a wrench some as well.

Need4Spd · 13th July 2009, 04:43

Quote:

I already replaced the fan clutch, question was in regards to re-securing the fan clutch nut onto the water pump. Some additional research indicates that spinning it on hand tight until it stops is adequate, and it will self tighten itself as it runs. I actually tightened down with a wrench some as well.

In theory it should "self-tighten" because of the reverse thread direction, BUT, it did fall off all by itself the first time, right? Probably the pressure you put on it is enough to keep it from happening again. FWIW, I replaced mine recently and found it quite tight, so taking it off required a special tool that holds the pulley from rotating. I also read how others had managed to remove theirs by jamming the pulley with a large screwdriver but I couldn't find quite the right angle to do that. I found that trying to hold it that way met with the "rubbery" feel you describe. I was also concerned about damaging the pulley or the take-up idler. So, I bought a tool that holds the pulley from turning from Pelican parts. Because the original unit was held "tool-tight," I tightened on the new one with similar torque.