BMW Can't Fix The Issue - What To Do?

[Sohaib-ijiiv]

Hi All,

I had a horrible hissing sound coming from the engine bay in my 07 335i which I took in to BMW under my comprehensive warranty.

After diagnosis they said its the AC compressor and tensioner pulley which they replaced.

Picked the car up and there was a squealing sound coming from the drivebelt region but I thought nothing of it, but sadly the noise was still there on cold starts and went once the car was warmed up in the following days.

Took it in again saying the noise wasn't there before and only after the AC compressor and tensioner work did it rear its head. They investigated and said I need a new belt.

Paid out of pocket for a new belt, still got the noise.

Took it in 2 weeks ago and they said its the alternator, replaced it. Noise is still there.

I've lost my mind a bit with this and was wondering what the best way to proceed with this is?

Complaining to head office results in the dealer calling me, me bringing the car in and nothing getting rectified.

[b14]

Did they change the idler pulley too? Should have done that when they did the tensioner, it can cause squeals. Most squeals will come from the tensioner or the idler. The next port of call would be the power steering pump, after having replaced the others.

After the alternator, AC compressor and PAS pump the only other possible cause would be the crank pulley but that really can't be what is causing it. Some garages will use a stethoscope to find out the exact cause of a noise like this, before they replace anything. That would be what I'd suggest is done, probably at an independent BMW specialist.

[stevemcs]

Surely they would remove the belt and run it and see if the noise comes back, if it does then it has to be something belt driven, if its still present then the fault is elsewhere. What type of noise is it ?

[gizlaroc]

This is why I will never use a main dealer.

They don't diagnose anything, the guess, throw new parts at it, at your expense, and see if that has fixed it, rinse and repeat.

Take it to a decent indy garage.

[dasbimmerowner]

Email to head office; you pay the warranty for it to be fixed, not for them to keep throwing parts at it and hoping it'll go away.

You could also try an alternative dealer.

[Sohaib-ijiiv]

They didn't replace the idler pulley far as I know.

Emailing head office just results in a loop of the dealer contacting me, taking the car in, something gets replace, issue is still there.

My other closest dealer from a friends experience is even worse (taken his car 9 times for an oil leak which they can't fix).

[Jaybmw]

Hissing ? Not a vacuum leak ? Brake servo or any lines ? Can you hear it if you press brakes ? Tired now so not taken in the full post but quick suggestions sometimes help

[Sohaib-ijiiv]

Its a squeal on cold starts that goes soon as the car warms up.

I've told them numerous times its a pulley or something, but of course am ignored.

[Jaybmw]

Cool. I'll assume you went out and sprayed each belt and pulley with some water ? Ideally a must to see if said noise changes or goes away, strange it goes away when warm

[steveo3002]

ask around on forums for most competent dealer in your area , then try them