Firstfives.org

When the car is stationary should you be able to move the fan?.

What I mean is does the fan spin freely when the engine is stopped and only spin with the engine when a certain speed is reached?

canada karl wrote:What I mean is does the fan spin freely when the engine is stopped and only spin with the engine when a certain speed is reached?

That is not really how it works. The fan has a clutch system that is activated by heat. When cold, it should spin freely. As the motor gets hot, it will engage the fan. But my understanding is that it is not an "engaged" versus "not engaged", as it is just an increase in the clutch friction.

If you find that your clutch is shot (they do not last forever), I have a brand new Lemforder for sale. This is for the bolt on version, not the spin on fan.

Google search previous posts for full explanations of how they work, two types, removal, etc.

(sorry for lateral post)

Will fan turn on when ignition is turned off on a '79 528i ? (I didn't see any forum members named "lefty")

carlsturm wrote:(sorry for lateral post)

Will fan turn on when ignition is turned off on a '79 528i ? (I didn't see any forum members named "lefty")

For the radiator fan to turn, the engine must be turning.

Blaise wrote:

carlsturm wrote:(sorry for lateral post)

Will fan turn on when ignition is turned off on a '79 528i ? (I didn't see any forum members named "lefty")

For the radiator fan to turn, the engine must be turning.

Except for the case the fan isn't original with visco-clutch.
I've seen a lot of examples with non-originals electric fans, installed directly on the radiators (for M30 and other engines that require fans, bolt on visco-clutch over the water pumps). In that case, after the HOT engine is turned off - for a little period of time, for example - a minute, the electric fan will be ON - it gets power through a thermo-switch (relay) directly from the fusebox.
It will cool the radiator and the engine a little bit, after the hot engine is turned off, but not so effective, because the water pump doesn't move the cooling liquid. But it is better than nothing...

ty Blaise & Alexander

my newer BMW fan sometimes turns on after I've shut down motor. I've been trying to diagnose cooling issue on my E12 and haven't yet put my hands on the radiator to see if there are cool spots.

I really don't understand - what kind of fan you have.
If the fan is original with visco-clutch - it is impossible it could turning independently after the engine is off and the crankshaft is not turning. I'm not speaking about the case you are cranking the engine, before the engine starts - then the fan is turning.
If your fan is electric - only then the fan could continue turning after stopping a HOT engine. Maybe you have an aftermarket electric fan.

Do you have an original or aftermarket air condition system with additional radiator section and fan?

If you can post a picture of your fan - then we can see - if it is installed on the radiator and has some wires or it is installed through the visco-clutch on the belt driven water pump.

TO CARLSTURN: as simple as it is to put hands on the radiator to check for cool spots, what you're actually saying is you want to rely on us, but, you don't want to do anything. C'MON MAN! Just do it! Oh, that's Nike.

I have been having cooling issues and about three weeks ago I could no longer drive the car in traffic. I believe I have just solved the mystery.

I first thought my fan clutch was not working, engine hot and fan not engaging. I then thought the electric fan was turning on and cooling the fan clutch. And I just noticed a cold spot right in front of the fan clutch. I removed the fan clutch and I could actually hold my hand on the radiator, inches away it was 95 C next to the thermo sensors for electric fan.

I'm a bit surprised the fan is not that old. It is a e28 upgrade. I will take it in and have it serviced.

Good for you Anthony! Pay att'n, CARLSTURN!
If you buy a book, you can also see just how easy it is to remove the radiator. Top two bolts & pull it out after you remove the hoses! If you're nice, I'll give you a tip on the best way to do it. Tried & true.
Okay, you're nice, just not motivated, so here's my tip from this website:
before you pull it out, wedge a thin piece of cardboard, like a giftbox in between the radiator & fan. That way you won't damage the radiator fins, or, take the whole car to the shop & make sure they don't damage the fins, but, you may never know since you haven't gone hands on yet.
I'm the biggest procrastinater around, so, I guess I understand!

Thanks for the advice guys. Once I fix this I'll report back what the specific issue was. No shortage of hot weather to test the cooling system with.

I took the radiator to the shop but do to the fact it is aluminum and plastic it cannot be taken apart-like a bronze radiator. So time for a new one.

Oh well. I'm glad I still have an E12 radiator in Rosallina.