Annoying noise wont go away!

I have an 02' 745i. About a year ago it started making squeaking noises which were in accordance with the RPM's. When I started the car it would squeak sometimes for a couple seconds and sometimes for a minute or two. When the squeaking became more frequent I took it to my BMW tech who works out of his house (also is employed at the local dealership). He could not find an obvious problem with it but replaced the drive belt and a pulley and the sound went away for about 3 or so months. The sound then slowly started to come back but was infrequent and only lasted a short amount of time. This past week after it had been sitting for about 2 weeks it started to do it again and this time its much more violent and doesn't go away. WHen I start the car it sounds like a constant screach for about 2 minutes and then wavers to an eventual stop and goes away but only because it's idling (500 RPM). When I press the gas pedal it comes back (throughout 700-2700 RPM) and goes according to the RPM's(the higher the RPM the faster it chirps). When I have it in gear and am driving it makes the loud constant screech when I'm turning the wheel and gets progressively louder the farther I turn it. It does not matter if I'm in drive or reverse the noise occurs in both. When I'm driving straight however, the sound seems to fade and sometimes go away. It also seems to act up with the change in temperature as far as being louder and more constant.

my belt got wet with coolant and the noise would not go away... we dried the belt and all that.

then i replaced the belt and the noise went away... funny thing that NO tech knew about this. they were telling me the belt cannot do this and all that

you must have a some kind of leak on the belt

try to put little WD40 on belt and see if its go away

i would start with water... when i had that noise i poured some water on the belt and it went away... for 2 seconds.

at least you would know if thats the problem.

Go to autozone and buy some belt dressing. You spary it on ure belt and it quites it down. OR MAYBE YOU NEED A NEW ONE

Belt dressing definitely. Especially if you replaced the pulley already. Btw. Did you try to steal my name?

I assume the right belt was used and that it hasn't come loose. I don't know how the drive belt is routed or if there is a tensioner but it may be the belt was put on too tight and has stretched.

IMHO, I would not use WD-40 and in past experiences I found that belt dressings to be a temporary fix to the problem.

Funny thing is I just had a coolant leak fixed and now that i think about it the noise started right after my tech changed the coolant about 10 months ago. I would assume he put the right belt on it because he seems to be very knowledgeable other than this noise I'm having. I'll try some water on it and see if it makes a difference and go from there


Btw haha no Wilk187 I just used the last part of my name and added 187. funny coincidence tho

Originally Posted by Chitown-Irish

I assume the right belt was used and that it hasn't come loose. I don't know how the drive belt is routed or if there is a tensioner but it may be the belt was put on too tight and has stretched.

IMHO, I would not use WD-40 and in past experiences I found that belt dressings to be a temporary fix to the problem.

wd40 definitely not a belt dressing by the way many tech using that to check that problem, and me too, it can route you if belt and pulley surface problem, if problem there no dressing for that just changing belt

After all this time of my tech not knowing what the noise was I poured some water on it this morning and the noise instantly went away. I feel stupid but at least I know what the problem is and that it's not gunna be an arm and a leg to fix. I'll get some belt dressing tomorrow. After all the BS I've been through with this car maybe when I get my new one next year I'll have better luck.

Thanks to everyone who responded it's a load off my mind.

Glad to hear you figured out your issue. I'm just starting to experience the same issue too.
Bros here are super helpful... this forum rocks.