Car making funny noise [belt slipping]?

MPWR · 19th February 2007, 10:11

My cars done 20k miles in 18 months and so far hasn't missed a beat. Recently its started making an intermitant noise similar to how an alternator would sound with the belt slipping. ( I am pretty sure its not the alternator)I have taken it to the dealer but it didn't make the noise! Whan it does you can hear it in the car and it sounds quite loud externally. The noise is coming from the right side of the car as you look towards the engine. The nosie is getting more regular but still not there the whole time and it doesn't seem temperature related.

Any clues?

M5interlagos · 19th February 2007, 12:05

Had a similar issue on mine at 15k miles. If it's the same thing as my issue then it was more evident when idling or approaching junction and then idling - and more pronounced after a long run. Had 2 goes to get it to work when I took it to dealer without success but, on 3rd occassion they had their snr engineer come out in the car with me and he heard it - "that doesn't sound right". New clutch, flywheel etc and all is fine now.

MPWR · 19th February 2007, 14:21

M5interlagos I think you could be right, just been in the car and the noise does seem to be linked to having the car in D or R i.e. put in in neutral and it seems to go.

Booked in the garage next week for them to investigate. Cheers

Lindross · 20th February 2007, 17:21

I've had the exact same issue. brought it in twice and both times they could not reproduce it and stated the noise on the belts was standard as the car warms up. My noice is a loud rattle which I hear coming through the vents on the inside and it doesn't always occur. Have you been able to reproduce it at will? What specifically did BMW replace M5interlagos when they fixed yours? Thanks!

M5interlagos · 21st February 2007, 12:06

they replaced the clutch, flywheel and various bolts/nuts etc - have warranty invoice if you want more details however, I may have spoken too soon as the noise returned again yesterday during a 200 mile round trip!! Will be speaking with dealer again today. Symptons appear when in S1 & 2 (not D) and in slow moving traffic or when idling whilst in stationary traffic either during or after long journey. Seems to come when apply small amount of revs to allow car to move forward whilst in queue of traffic, once get above S3 it goes. It sounds like a fan noise (definately not a rattle) which I can hear above radio (as long as it's not on too loud). It happened again after a cold start yesterday as well.........really not sure what it is. Will keep you posted once spoken with dealer.

Lindross · 10th April 2007, 03:47

Did they find what was causing the noise? I had my M5 in for a few things and asked them to look at the noise again. They checked it against another M5 and claim this is standard noise. This is the third visit for this problem. I get in the car, drive home and pull into the garage in S1 idle only to hear the rattle again. It sounds like a belt hitting the plastic cover on the right side (when facing the car) of the engine. I am not sure what is under this black square cover (one on each side of the engine) but it is difinetly rubbing producing a sound that comes through my vents. I am close to selling this car if they can't fix the issue soon. The noise is annoying and embarassing when you turn it on or idle in front of people. My only issue is BMW doesn't seem to hear the noise as its intermittent. Any suggestions?

MonM5 · 10th April 2007, 07:17

Lindross: "I am not sure what is under this black square cover (one on each side of the engine) but it is difinetly rubbing producing a sound that comes through my vents."

What is under that black square cover are your air filters. I would look in there to see if there is something lose (which could be very dangerous for your engine as this is your intake and you wouldn't want anything to get in to your engine). You should be able to open it with a flathead screwdriver by prying the clips lose.

Hope this helps.

Lindross · 10th April 2007, 16:30

here is a picture from where the rubbing noise is occuring. Can you confirm what is under the black cover. It sure seems like there are belts moving underneath it which start out loud when the car is cold and get quiter as it warms up. Thanks!

Michael_s · 10th April 2007, 16:56

Quote:

Originally Posted by Lindross

here is a picture from where the rubbing noise is occuring. Can you confirm what is under the black cover. It sure seems like there are belts moving underneath it which start out loud when the car is cold and get quiter as it warms up. Thanks!

I dont know whats under there but its not the air filter.

Barry Lausch · 10th April 2007, 17:22

Quote:

Originally Posted by Lindross

here is a picture from where the rubbing noise is occuring. Can you confirm what is under the black cover. It sure seems like there are belts moving underneath it which start out loud when the car is cold and get quiter as it warms up. Thanks!

That my friends is the vanos accuator assy. Mine made a noise that sounded metallic in nature but in reality was air entrained high pressure oil in the vanos system. Needed to be bled down, or could be the accumulator in the vanos loop that does the bleeding automatically.