Just did the "newspaper" test on the fan and the fan slows down to a stop when i wedge it into the fan.
I carried the test out on a cold start (doubt that makes a difference).
I'd like to know what the next step is.
Do i just order part number: 11527830486 "Fan Coupling"?
Should also get a new fan (P/N: 11521712110 $52.18) and fasteners (P/N: 07129905536 $0.99/ea). The fan is subject to thermal fatigue and high centrifugal loading which, can lead to catastrophic failure. :wrench:
Now that you say that, i've just tried it after getting the car warm and the fan doesn't slow down. It ripped through the newspaper and wouldn't stop... :eek7:
This was the same problem I had; clutch fan wasn't working. All the tests indicated a bad clutch fan. Short story, car always ran cold in the winter/normal in the summer-temperature wise. After 8 years, all of a sudden it started running hot, 105 KTEMP, in the summer! I thought, no brainer, gotta be the clutch fan. Spent the $, got the clutch fan. Took it out of the box and was it stiff; gotta be the problem. Installed and was happy it was the clutch fan- not! I'd told my mechanic about my great troublesshooting skills; he was impressed I would be able to figure it out all by myself. Went to visit after the repair, still running hot. After a couple of minutes, he asked to see the install. ? He was impressed I figured out the reverse threads; and then asked why both of the radiator hoses weren't the same temperature. One being "HOT" and the other "Not HOT." I told him, "Oh, tstats always fail in the open position, in these cars!" They don't!
If the car was just warm, then you have a bad fan clutch it seems. If it was HOT, then the fan clutch should be hard to stop.
Start the car, run it around a small block if you're able, then test. Or start it, let it idle a few minutes, rev it a few times, then test. At that point if it is still ripping you newspaper, I would replace it. :M5thumbs:
TIS says the fan clutch "switch on" temp is 95 deg C and the "switch off" temp is 60 deg C. What that means in effect is that the clutch starts to engage when the air coming out of the rad and blowing over the clutch is 60 deg C, and is fully engaged (i.e. fan spinning at same speed as the water pump pulley and making lots of noise) when the air temp is 95 deg C.
So a minute or so after a cold start, when the silicone fluid in the clutch has stabilized, the fan will be effectively free-wheeling and can be stopped with a rolled-up newspaper. When the air temp coming from the rad hits 60 deg C, the clutch engages and the fan will start to shred the paper.
If the fan shreds the paper when cold and makes lot of noise at high rpm, you may have the dreaded fan clutch lock-up which can overspeed the fan, disintegrate the blades, and take out the rad and hoses and dent the hood.
When the engine is cold, the fan clutch isn't engaged and driving the fan, but there is still a but of viscous drag from the silicone fluid in the clutch so the fan spins halfheartedly with the clutch. All it takes to stop the fan spinning is holding something forgiving against the fan blade tips. A rolled-up newspaper is a favourite. Hell, I've used my finger tips.
Because the clutch "engage" setpoint is when the air coming through the rad is around 95C, even when the engine is warmed up, you can usually still stop the fan since the aux fan is good at keeping the rad temp below 95C.
Going to replace my clutch and fan. You can get the URO or VEMO brand fans for half the cost of the "Genuine BMW" an blade. Anyone have experience with either brand and are they OK to use?
Do the test twice once cold once warm. If it stops cold you are good. Warm it might stop because it is not warm enough to be fully engaged but likely the air will be warmer than 60C so it should be harder to stop. If not then it could also be bad, but if it was harder to do than cold you are likely good.
Its not always the fan clutch failing if it failed the newspaper test (i.e. fan free spinning when engine warm). One time the temperature gauge in my other car (1997 Mercedes E420) was showing high temperature about 110 celsius especially in stop-and-go traffic with AC on. I tested the fan with a roll of newspaper and was able to stop the fan when the engine was running very hot. I proceeded to replace the fan clutch and still doing the same thing. Finally, the mechanic found out the radiator was blocked internally because the central portion of the radiator was stone cold and caused the bi-metallic strip at the front of the fan clutch not feeling any heat to activate the locking mechanism for the fan. In short for this case, it was a bad clogged radiator and not a bad fan clutch.
Sorry to bump this thread but was hoping to ask for some confirmation. Last night my ktemps got to about 106 degrees Celsius. I parked it and turned it off. It was raining heavily out so I couldn't remember if I heard the fan going or not but when I popped the hood right after parking, the fan was not moving. I tried to move it by hand and it was spinning maybe a cm left and right, but i didn't push too hard. I don't want to try and start it again in case it's seized completely otherwise I'd perform the tests in this thread. Could something else have caused my temps to go up and the super tight fan is normal? I thought that the fan spun more freely in the past but I don't know if I am just misremembering.
Thermostat and aux fan is a year old, the mech fan is (likely) original at 94K kms. I don't mind replacing it now if that's what it is but I want to be sure it can't be anything else while I'm at it.
Usually the fan clutch fails seized so it is running full speed. The problem with that is obviously not overheating but the fan blowing apart and tearing up your rad/hoses/hood.
Rarely the fan can fail the other way, and not fully engage which could cause overheating.
There are many other issues that can causing overheating. Are you getting a CEL or any codes?
No cel. Haven't checked with inpa yet though. I had to leave it parked so it's a bit away still.
Yeah i figured if it'd have failed it'd have been spinning freely. This was the first time it's ever gotten >95 I think, or past center for whatever that's worth.
I just went to the car now. Had another look, no codes at all. The fan spins tightly and I guess it's supposed to be when the car is off. I started it up and it was spinning. Didn't get a chance to test it nor did i bring it up to any temps. So I am not sure what caused the overheating but I guess suspecting the fan clutch was premature. I'll have to look into other reasons for overheating.
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