Fan clutch question

[n thomas33]

So my 89 535i was overheating at low speeds and idle,which it turn caused the upper radiator hose to split, so long story short i need a new clutch. Now, I didnt know that they cost an arm and a leg, and the cheapest one would take about a week to get here. However, I happen to have a fresh fan clutch in my 89 325i, and I was wondering if that would suffice until I can get the m30 clutch. I already know that the e30 fan clutch wont bolt straight up to the e34 fan, but I'll figure something out for that. Thanks, Nick

[zubbie]

Hmm... if you can make it fit without hitting the rad / shroud then go for it but I would be interested in seeing your solution.

I've also read about porsche guys rebuilding the fan clutch by replacing the viscous fluid in it.

[Binjammin]

It should fit, but you'll probably have to bring the fan over with it. IIRC the m20 clutches had a different fan bolt pattern than the m30 clutches. The fan should still fit in the shroud. Assuming it fits, it will work fine.

[n thomas33]

so I hooked up the m20 fan clutch to the car and it works and stays cool as long as I'm moving, but when I stop the temp needle starts creeping up, but as soon as I start moving again, its fine. And I did the newspaper test on this clutch and it is good. I figure that I can get by with this one until the other one comes

Oh, also, I was using the m20 fan as well, because the m30 is a). too big. b). doesn't have enough holes

[zubbie]

so I hooked up the m20 fan clutch to the car and it works and stays cool as long as I'm moving, but when I stop the temp needle starts creeping up, but as soon as I start moving again, its fine. And I did the newspaper test on this clutch and it is good. I figure that I can get by with this one until the other one comes

This sounds a bit fishy. A working fan clutch will spin at idle and provide plenty of cooling. You sure you don't have an air bubble somewhere? or a bad thermostat? Or a bad water pump?

[russiankid]

You can run it without the shroud for the mean time if it does hit the shroud. And these clutches last a long time, so its not really that much.

[Binjammin]

so I hooked up the m20 fan clutch to the car and it works and stays cool as long as I'm moving, but when I stop the temp needle starts creeping up, but as soon as I start moving again, its fine. And I did the newspaper test on this clutch and it is good. I figure that I can get by with this one until the other one comes

Oh, also, I was using the m20 fan as well, because the m30 is a). too big. b). doesn't have enough holes


Your car overheated, you need to replace the thermostat. The car running warm like that means you've either got a nasty air bubble or you popped the head gasket when it over heated. You need to bleed the system, and you need to do it with the heat on in the car at full blast, and the blower all the way up.

[n thomas33]

Well, I bled the system before my drive to school this morning, and there wasn't even a hint of overheating. It was a brisk morning, if that has anything to do with that, but I was pleasantly surprised, because it seems as if though the m20 clutch should last me until the correct one comes in, which I ordered last night, along with a window regulator so I can pass inspection...hooray! :D haha

[Binjammin]

Did you get a lot of air out of the system?

[n thomas33]

I guess, I mean, when I bled it this morning I did have the heater on, and I drove back from my girlfriends house (about 45 min) without the temp guage moving once it got to op. temp.

[Lax7]

hey my 535i overheats too but not as fast as thomas. its kindda confusing but here goes the story. when i drive during the day where it is extremely HOT( living in indonesia) with the AC on, the temp gauge starts to go up a little bit reaching the 3/4 line. however, i turned off the AC and kept going to gain some speed and air and it finally goes back to normal. one day, i drove it again WITHOUT AC and was stuck in complete traffic for 2 hours. the temp then started to rise again but in a slow motion up to the 3/4 line. i then turned on the AC and it does the same and not decreasing it however.

my suspicions of this problem might be:
- auxiliary fan ( it spins kind of slow and u dont realy hear the loud fan noise)
-fan clutch( at times it doesnt spin that fast and u cant hear the loud whirling noise when u step on the gas)

i have no idea how they are suppose to sound or work, becase usually the sound of it can let you give you a guide whether or not its working properly.

+ regarding the newspaper test. can someone write a small summary of how to do it and what am i suppose to be getting?

i dont suspect taht it has to do with the coolant because i have neevr had to add more water. it stays at the same level all the time when i check.

Thanks a lot

Chris

[Binjammin]

Chris it sounds like you're right on the money with the aux fan and fan clutch. Test those both and get back to us.

[n thomas33]

The newspaper test: turn on car, let it get to operating temp. Roll up a newspaper and stick it in the fan and if the fan stops, your clutch is bad.

[AquilaBMW]

The newspaper test: turn on car, let it get to operating temp. Roll up a newspaper and stick it in the fan and if the fan stops, your clutch is bad.

Ummm.... what happens if the fan doesn't stop? As in - the paper and your hand?:eek:

[Binjammin]

Ummm.... what happens if the fan doesn't stop? As in - the paper and your hand?:eek:


Well, you're not shoving your hand all the way into the fan... you're just using the rolled up newspaper at the edge of the blade. It's not like you're going to get your arm sucked into a printing press.

[Lax7]

hey guys!

so the results:

Fan clutch: seems to work fine. i had bits of newspaper flying all over the place.

Aux Fan: i have no idea how its suppose to work. does it turn on also WITHOUT having the AC on? if it is, this might be the problem. because comparing to my other cars, the 535 sounds a bit slow. and so as my 750 bydway.

how do i test if its bad or good?

thanks for the help guys.

[danielz40]

Okay I have an M3 but they may work the same. On my pass side of radiator there is a thermal switch. I take out the plug and put it a U shaped piece of wire to bypass the switch. There is a common, a low speed and a high speed connector. Connect the ground to one of the others. Trial and error will show you the high and lo and ground. if you get nothing chances are you have the hi connected to the low and not the ground. Anyway, just tape it down to high and drive it around that way and see if your fan works. If you can't really tell the high from the low or can't find high, you probably have a bad fan.

Hope you understand this. Just common sense to me cause you are just physically doing what the thermal switch does, only doing it manually.

Good luck.:)

[Lax7]

well, the fan does work. but i think its the high speed does not work. i remember when i went to the shop once and they told me to get a new aux fan motor. so i guess i'll have that checked out.