My 08 335 coupe with 3k miles gets this miter saw like spinning noise that last about a second or two and happens about every minute when car is shut off. This doesn't happen all the time but I only noticed it happen when the car is turned off and often 30 minutes or even hours after I last drove it (thus it can't be any cooling mechanism). Key- the noise is coming from right side of the engine (looking from the front) where the filter and turbo is located. Sorry if I totally messed up the turbo location.

I asked the dealer but there was no noise at the time so he said it was something normal. Any thoughts? This can't be normal!

hmm it could be the car's cooling system cooling down the turbos. Is it like a buzzing noise? I'm sorry, I've never heard a miter saw before.

My 08 335 coupe with 3k miles gets this miter saw like spinning noise that last about a second or two and happens about every minute when car is shut off. This doesn't happen all the time but I only noticed it happen when the car is turned off and often 30 minutes or even hours after I last drove it (thus it can't be any cooling mechanism). Key- the noise is coming from right side of the engine (looking from the front) where the filter and turbo is located. Sorry if I totally messed up the turbo location.

I asked the dealer but there was no noise at the time so he said it was something normal. Any thoughts? This can't be normal!

I believe it is the oil cooler working to cool down the turbos (the oil cooler is inside the right front wheel well). You should only notice it when you've been driving the car pretty hard or it's hot outside, otherwise it doesn't come on after you shut off the car.

My car does the same thing. Must be normal.
I also hear the water sensing mechanism for the brakes working when I hand wash my car.

I also hear the water sensing mechanism for the brakes working when I hand wash my car.Unless the car is moving with the wipers on while you're washing it, I doubt it.

hmm it could be the car's cooling system cooling down the turbos. Is it like a buzzing noise? I'm sorry, I've never heard a miter saw before.

How can it be a cooling mechanism when sometimes occurs with the car ice cold in the middle of the night? I usually hear it when washing the car and to do that I only drive the car out if the garage so that hardly gets the car warmed up. It has happened after driving as well but I doubt it is a cooler issue. Also, it doesn't come from the wheel but side of the engine where the turbo is. I have yet to push the car to the red line and I ordered and then bought the car new with 2 miles on it. It's very annoying and I'm the type of person who listens for these types of noises in the car.

I would just take it to the dealer and asks them, they'll prolly tell you that it's normal. I'm still leaning towards the cooling though. If it makes you feel better, just take it to the dealer, they know a hell alot more than me.

Water pump running coolant after shutdown through the turbo's. I believe I read the turbo's have water jacket. Normal though. Also, I believe there is a recirc pump for fuel and vapors. I hear the same noise you are describing. If you look it is coming from the black box housed just in front of the rear driveline on the driver's side. Also normal.