BMW E36 timing chain, tensioners and rattle
Does the E36 six-cylinder have a timing belt or chain, and when is the chain replaced?
Six-cylinder E36 models have had a timing chain from 1991 onwards, including Finnish-market cars. The manufacturer gives no replacement interval for the chain, and it is considered maintenance-free. The chain is usually replaced only when the engine is opened up anyway, at over about 300,000 km. A stretching chain rattles.
What causes the M50 engine rattle at around 3000-4000 rpm?
The suspected cause is slack in the timing chain tensioner: the piston and sleeve of a worn tensioner wear, and oil pressure can no longer tension the chain properly. The tensioner of the secondary chain, that is the chain between the camshafts, usually loosens first.
How do I replace the chain tensioners on an M50?
The primary chain tensioner is removed from the side of the timing cover, and no other dismantling is needed. Replacing the secondary chain tensioner requires removing the chain between the camshafts. A cam locking tool makes it easier to align the timing. If the noise continues after replacing the tensioners, check the sprocket teeth and the chain tension.