Fan clutch Q

[schnell944]

So, I was poking aroud today, trying to figure out the best way to turn the engine. I took a look at the front of the fan (facing the radiator) and thought the metal strip that is attached to the fan clutch pin was a safety strip covering a bolt to release the fan(hey, it was covered with a lot of dirt :p In any event, I pried the metal strip just a bit until I saw the attached pin and realized that wasn't what it was. How sensitive is this piece to the proper function of the clutch. it doesn't look like the metal strip was bent very much, if at all, in my efforts. it will move in and out very slightly with the push of my finger(where it attaches freely at one end)....could I have possibly messed up its function? As far as I can tell without driving much, it seems to be working ok. tia

[Bill R.]

Yes you did mess it up. Its a bimetallic strip that reacts to temperature and when hot air hits it , it changes shape as it heats up and raises and lowers that pin opening and closing an orifice



So, I was poking aroud today, trying to figure out the best way to turn the engine. I took a look at the front of the fan (facing the radiator) and thought the metal strip that is attached to the fan clutch pin was a safety strip covering a bolt to release the fan(hey, it was covered with a lot of dirt :p In any event, I pried the metal strip just a bit until I saw the attached pin and realized that wasn't what it was. How sensitive is this piece to the proper function of the clutch. it doesn't look like the metal strip was bent very much, if at all, in my efforts. it will move in and out very slightly with the push of my finger(where it attaches freely at one end)....could I have possibly messed up its function? As far as I can tell without driving much, it seems to be working ok. tia

[schnell944]

lame. that's what I get for poking around, I guess. I didn't move it very much though.

[schnell944]

So, the strip doesn't look to be deformed and still seems to function properly. It clutches up the first few seconds when I start the car cold then slows down and speeds up a little. The fan goes faster when I raise the engine speed a bit. It doesnt clutch up when I leave the car sitting for a bit though, but the engine temp stays right in the middle. This is probably because it isnt too hot outside now. It isnt very easy to stop with the newspaper test. Does this sound like things are still right? I may snag a fan cluth from the salvage yard for comparison tomorrow. I've never really paid much attention to its function before and am now a little paranoid.

[Bill R.]

If its too cool outside then the radiator never will heat the air up enough passing over the fan clutch to tell whether its engaging at the right time or not. Here's the specshttp://www.bimmernut.com/%7Ebillr/images/fanclutch.jpg





So, the strip doesn't look to be deformed and still seems to function properly. It clutches up the first few seconds when I start the car cold then slows down and speeds up a little. The fan goes faster when I raise the engine speed a bit. It doesnt clutch up when I leave the car sitting for a bit though, but the engine temp stays right in the middle. This is probably because it isnt too hot outside now. It isnt very easy to stop with the newspaper test. Does this sound like things are still right? I may snag a fan cluth from the salvage yard for comparison tomorrow. I've never really paid much attention to its function before and am now a little paranoid.

[shogun]

Here you can see the strip
http://bmwe32.masscom.net/johan/fan_clutch/fan_clutch.html
But there are also clutches with spiral type bimetal
http://img153.auctions.yahoo.co.jp/users/7/0/8/2/testinium-img600x450-1156412156fancluch1.jpg

[schnell944]

that's unfortunate....I guess I'll just have to wait till it's hot outside. Maybe I'll pull a spare out from the yard incase I'm up a creek when the hot weather comes.

the strip doesn't look to be deformed by my efforts. I wonder how sensitive it is.

One more clutch related question. I dont have the special tool to hold the pully when tightening the fan nut. If I can get the nut tight enough so the wrench requires a firm bang with my palm to free then nut, is that good enough?

[Bill R.]

give it a couple of light wacks to tighten it up.



that's unfortunate....I guess I'll just have to wait till it's hot outside. Maybe I'll pull a spare out from the yard incase I'm up a creek when the hot weather comes.

One more clutch related question. I dont have the special tool to hold the pully when tightening the fan nut. If I can get the nut tight enough so the wrench requires a firm bang with my palm to free then nut, is that good enough?

[schnell944]

give it a couple of light wacks to tighten it up.

thanks for the help guys. after seeing the restoration page shogun posted where it seemed like the bimetal strip was manhandled a bit, I feel a little bit better. I thought maybe it was a super super sensitive piece... Just slightly worries me as I will be moving to DC soon....scared of those hot steamy summers.

Better yet, I think I may just pull the bimetal strip out of a salvage yard car just so I can sleep a little easier.

[632 Regal]

for what it's worth, if it was all gunked up and greasy the fluid is leaking out of the fan clutch. If I was you I would just get a new clutch and save it for a warmer day. The bimetal strip is very sensitive, should be good in the cold but when it warms up who knows what can happen.

[schnell944]

fair enough. I guess I'll think of getting a new one when the weather gets warmer and I have the funds. it very well could be the original clutch. I havent replaced it and I can't see it in the paperwork since new...