Re: timing chain noise when cold (archive)

If you are sure the noise is from the chain, then it can be caused by many things. The most likely problem is a leak. The tensioner holds oil behind a piston. When you shut off the engine, the oil behind the piston may leak out slightly. Then when you start the car up after a while, the piston doesn't have the help of the oil behind it. The chain rattles for a while, but eventually the oil reservoir fills up again, which is why it silences after a while. You will have to reseal the tensioner assembly. There are two aluminum washers and an o-ring that will leak. Resealing will take about an hour or so to fix. Get new washers and the o-ring. A new tensioner piston and assembly may not be necessary. They cost us about $100 here in the US. I've had great results from installing new washers only.

The bleeder is more of a filler, really. You can use a syringe to inject oil into the piston assembly after you reinstall it. That way there is oil in there to prevent the noisy chain rattle. Otherwise, the reservoir will have to fill up on its own, and that may take up to 30 minutes of driving. It's very annoying.

I have a noise when I start my engine only when it is cold. It is probably cold piston slap. Since your engine isn't that old (115 000km isn't that old) this is probably not your problem.

Many European M3 owners suggest changing the entire timing chain assembly every 150 000km. They say that the chain may jump a tooth, thereby destroying the entire valvetrain. Here in the US, our M3's don't seem to have a problembut our M5's do, however. You will have to buy all new sprockets, tensioner rails, and chain. The parts are rather expensive, and the labor is intensive. But it is stil cheaper than a whole broken engine!

Viel Gluck!
James
james_535@yahoo.com
88 M5
88 M3
83 535i

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