In Reply to: Re: Noise at Start Up posted by Angus on June 05, 2000 at 12:34:16:
I own a '91 M3 convertible and have only had it a few days. It only has 55k miles on it and it is making the same noise on start up. Is it not a bit early for this to be happening? Could it possibly be anything else?? I'm going to get the dealer who sold me the car to change the tensioner anyway but if there's anything else it might be I'll get them to sort that as well! Cheers....
: John ,this is a common problem on these motors it is the timing chain tensioner .if the motor stops in the right place when turned off the tensioner will bleed down due to wear in the tensioner bore and pressure exerted on the tensioner by the chain pushing in back in (this condition is often made worse if the car is parked with the nose uphill and left in gear, motor then turns backwards as car rolls backwards to a stop).you are lucky if this is the first time you've heard this noise at 140,000 ,as most start randomly making this noise at about 80,000(how long have you owned the car ,maybe someone replaced the timing chain/tensioner previously).you can replace the tensioner (as it bolts to the outside of the timing cover)fairly easily,it is sold as a complete unit and if you follow the factory manual it can be replaced in a couple hours.but if you don't know the history of the timing chain (it must be replace every 100,000 miles)now would be the time to replace the timing chain and tensioner as this the noise your hearing is the chain slapping around until the tensioner gets oil pressure and the air bleeds out,and in turn applies pressure to the tensioner rail/chain. this could possibly break a badly worn timing chain leading to catastrophe (read new motor)