Humming after shutoff - BMW Forum

tonyp115 · 03-23-2006, 07:33 PM

I noticed for the 1st time today, (not to say its never happened before) that after a 20 min drive in my 01' 330i, a humming sound coming from the car after engine shutoff. it seemed to last about 3-4 minutes and was apparently coming from under the engine cover. The sound can only be described as a electrical hum like from florsent lights. the cooling fans wern't on. Is this normal?

///M Power · 03-23-2006, 08:52 PM

Asbolteuly. It's your Air conditioning unit discharging or some gibberish.

If that's what you're describing. Can you hear it from the cockpit? Does it sound liek it's comign through the vents?

Ocean02 · 03-24-2006, 10:51 AM

My car's been doing this climate control after-shut-off venting since I bought the car in December. It sounds like the electrical AC fan too. Not worried about it.

A funny thing though, while were on this subject. Has anyone noticed their AC/climate control "surge" in speed/intensity while the AC/climate control is on? I have noticed this sometimes. The fan seems to burst or surge to higher revs for fractions of a second at a time and then slow back down again.

This is not always, just sometimes. Any ideas? No big deal, but I was just curious. Kind of sounds like the AC is having an epileptic seizure.

Dirty_Tool · 03-24-2006, 12:56 PM

the surging is most likely a bad final stage resistor. Im sure if you do a search on this subject it will yield plenty of results.

e90_330xi · 03-27-2006, 05:17 PM

run the heat high for a minute or two, even if its 90 derees outside, remove some of the heat of out the cover...try it