hunnypuppy

This started today after I drove home in my 08 535i (e60).

The show the problem, see this video, this is EXACTLY what I hear.


After turning off the engine, remove the key. Wait for about 10 seconds and then this suddenly loud whirring noise for a split second followed by a constant whirring fan from somewhere in the engine.

The moment I do anything (close a door, insert key) to activate the car/electronics it goes away. Then again after everything is left alone for a minute or so (with key out) it starts again and continues.
It doesn't happen when the key is in or anything is active (bluetooth). Only when everything's off it starts the fan/whirring.

Anyone have any idea what this might be.

Thanks

twh

Some thoughts...

There is a fan nearby in the e-box. That's the box under the passenger side cabin air filter that houses the engine computer. I've replaced it in my wife's X5. It is a PITA to get out since you have to disconnect everything from the ECU to get to the fan. But, I don't think that is your sound.

I'd start by removing the engine plastic cover. You can provably get your ear down closer to various parts to better pin point where the noise if coming from. Getting the cover off isn't very hard and you can leave it off and still use the car while you are debugging.

hunnypuppy

Thanks will try it. It's kinda sporadic. Definitely not the passenger compartment, it's deep within the engine. What kind of a fan/whirring component would lie under/bottom/inside the engine that kicks on AFTER the car shuts down?

twh

I don't think it is your noise, but the E-box fan is in the engine compartment. See this thread:
Check engine error message on my E65 - Bimmerfest - BMW Forums
If you are standing in front of the car it is at the back left of the engine compartment. You have to take the cabin air filter out and then you can get to the cover to the ECU. The e-box fan is under that.

hunnypuppy

That I also thought it was the ECU fan but after listening closely it noise not at the back left it's almost sure to be coming from under the engine block. Wierd?

hunnypuppy

You know what you may be right, does this sound anything like my video (second opinion)?

twh

Wow...that one is making a lot of noise. Easy to debug. Take out the cabin air filter and pop the cover off the ECU. You don't have to take the ECU out or anything else in there to get a good listen. If it is happening, you'll likely know as soon as the ECU cover is off.

hunnypuppy

Good idea thanks

ucsbwsr

I am pretty sure that is your water pump, it will circulate coolant if it deems necessary to cool the engine. Once way to check is...

Turn the ignition on (do not start the engine), heat to full hot with the blower on low. Press the throttle fully to the floor and hold for 10 seconds, then release. This will activate the self-bleed process. The process takes about ten minutes and is fully automatic. During this process you should be able to hear the water pump moving the coolant and turning on and off.


During this process ideally you should have the car connected to a charger so it doesn't die but since your system is already bled I don't foresee that being an issue. There shouldn't be any harm with performing this test but do so at your own risk. It will allow you to confirm that the noise you hear is infact the water pump circulating.

Hope this helps,
Evan

ucsbwsr

Also, the pump is located towards the lower front passenger side of the engine block. It can be hard to see and if you have an xi like me the subframe sits directly below it, regardless you will have an easier time seeing/accessing it from below.

Evan