Electric Cooling Fan not working - E46 330i

[AcidBurn]

Howzit guys

I need the gurus on here's assistance please. I was doing a little research on my cooling fan not working but I don't seem to get a definitive answer telling me that replacing my cooling fan will definitely fix my problems. So I'm turning to the community for help/assistance in sort my problem.

Ok so where do I start. Friday afternoon I was running some errands, I got stuck in some traffic for 15mins, it was quite hot on Friday so I had the ac blowing. Moments later I felt ac blowing hot air and then noticed my heat gauge raising. Traffic eventually start moving and the needle dropped a little but not completely. I managed to pull on the side of the road to shut down the car. Gave it a few minutes to cool off, then checked the temp but it was still high I was far from home and panicked cause peak hour traffic will be starting soon. So I started the car up and decided to get going again but I shut off the ac, low and behold the heat gauge slowly started moving back to the center. I made my way home 25km's with no issues. Car stood most of the weekend and I drove it again this morning to work, no issues with ac on. However there is no traffic going to work.

Now just before I left work on my way home I decided to put the ac on to check if my fan is working and guess what it didn't. I left the ac running while the car was idling for 5 mins, still no fan spinning but the ac was blowing cold.

What do you guys suggest I do here, by a new fan, check fuses or what would be next. I don't have a scanner so I can't check exactly what is at fault all I know is my fan is not working.

I am scared to drive the car like this fearing head gasket damage or expansion tank blow out.

Please advise.

Apologies for the long post but wanted to be as clear and thorough as possible.

 

[moranor@axis]

start the car and open the radiator filler cap there should be a small amount of water spraying into the expansion tank at a steady stream near the top (if this does not happen its your water pump)

If stream is there close the cap and let the car get up to temp in the driveway

once up to temp rev it at 3000 for a few min to see if the temperature rises if it does then it is probably your fan so turn off the engine and let the temp come down

once at half temp again go for a drive stay close to home and in a safe area in case you have to stop to let the car cool try keep air moving over the radiator at all times if it stays at correct temp now then it is almost definitey the fan

once home let it idle again and give it 3000 RPM if temp goes up the same as last time and the fan does not come on it is 99% chance it is the fan

only other thing it could be is the thermostat but this will make it run cold at highway speeds you can try the highway to confirm once you are quite sure it is the fan just avoid traffic so it does not overheat

 

[444YYY]

Turn the AC on, if the electric fan does not come on. Check the fuse first. I've seen this before...

 

[AcidBurn]

Hey moranor,

thanx for taking the time out to respond. i did some more testing now in the drive way. this is what i have come up with.

i have just checked the big fuse in the glove box and it fine. i unplugged the fan plug and started the car, shut the car off and replugged the fan plug still nothing. put ac on and its cold but the ac pipes got very hot, obviously due to no air cooling the ac radiator. what i did feel when the car was idling is that the fan would give a little quick very very short spin for like a split second but i needed to keep my hand right by the blades, i felt this happen twice.

so is it still a broken fan or am i having an electrical issues.

guys im not skimping in trying to get out of buying a new fan but it will really kill me if i installed a new fan and it still doesnt solve my problem.

is there someone willing to borrow me a fan just to test...i know this is a long shot hehehehe. but hey, you dont ask, you dont get.

cheers

---

Turn the AC on, if the electric fan does not come on. Check the fuse first. I've seen this before...

ac turned on = check
no electric fan when ac is on = check
check 50 amp/or what ever fuse in glove box, all is fine = check

 

[moranor@axis]

fan is expensive for what it is I also did not want to replace it lol

does the car want to overheat in the driveway? you will have run it for a while to get up to temp and to get the needle to go higher if the fan is at fault

 

[OppositeLockMT]

Ever since my accident 4 years ago I've been running without an AUX fan, haven't experienced any issues what so ever regarding overheating etc. :fencelook:

I'd suggest you sort out your AUX fan if you can, not sure how the setup is on the M54.

 

[KPM3_30]

Ever since my accident 4 years ago I've been running without an AUX fan, haven't experienced any issues what so ever regarding overheating etc. :fencelook:

I'd suggest you sort out your AUX fan if you can, not sure how the setup is on the M54.

No AUX fan on the m54. Just one single engine fan responsible for all the cooling down of that engine bay. :hammerhead:

 

[Blue Shirt]

Attached is a nice description of the M54 engine and ancillary systems.

Page 36 contains information on the electric cooling fan and how it is controlled.

The electric cooling fan is now controlled by the ECM. The ECM uses a remote power output
final stage (mounted on the fan housing)
The power output stage receives power from a 50 amp fuse (located in glove box above
the fuse bracket). The electric fan is controlled by a pulse width modulated signal from the
ECM.
The fan is activated based on the ECM calculation
(sensing ratio) of:
• Coolant outlet temperature
• Calculated (by the ECM) catalyst temperature
• Vehicle speed
• Battery voltage
• Air Conditioning pressure (calculated by IHKA
and sent via the K-Bus to the ECM)
NOTE: If the ECM indicates a fault check the fan for freedom of movement
After the initial test has been performed, the fan is brought up to the specified operating
speed. At 10% (sensing ratio) the fan runs at 1/3 speed. At a sensing ratio of between 90-
95% the fan is running at maximum speed. Below 10% or above 95% the fan is stationary.
The sensing ratio is suppressed by a hysteresis function, this prevents speed fluctuation.
When the A/C is switched on, the electric fan is not immediately activated.
After the engine is switched off, the fan may continue to operate at varying speeds (based
on the ECM calculated catalyst temperature). This will cool the radiator down from a heat
surge (up to 10 minutes).

 

[Gizmo]

Ever since my accident 4 years ago I've been running without an AUX fan, haven't experienced any issues what so ever regarding overheating etc. :fencelook:

I'd suggest you sort out your AUX fan if you can, not sure how the setup is on the M54.

No AUX fan on the m54. Just one single engine fan responsible for all the cooling down of that engine bay. :hammerhead:

wrong. The auto has an aux fan in the front and a viscous behind the radiator. The manual has a electric fan only behind the radiator.

 

[KPM3_30]

Ever since my accident 4 years ago I've been running without an AUX fan, haven't experienced any issues what so ever regarding overheating etc. :fencelook:

I'd suggest you sort out your AUX fan if you can, not sure how the setup is on the M54.

No AUX fan on the m54. Just one single engine fan responsible for all the cooling down of that engine bay. :hammerhead:

wrong. The auto has an aux fan in the front and a viscous behind the radiator. The manual has a electric fan only behind the radiator.

Aha, thanks for the clarity! Mine being manual, I only noticed the electric fan behind the radiator.