Mercedes-Benz W203 M271: timing chain stretch and replacement
Mercedes-Benz W203 M271: how do you recognise a stretched timing chain?
Typical symptoms are uneven running, misfires and revs dropping. The chain can stretch or jump a tooth or more, which shifts the engine timing. Driving should be avoided until the fault has been repaired.
Mercedes-Benz M271: how do you check the condition of the timing chain?
Stretch cannot be judged by lifting the chain alone, because the tensioner has to be slack. The most reliable way is to compare the crankshaft and camshaft timing marks with each other. If a mark is wrong, the cause can also be a failed rubber damper in the crankshaft pulley.
Mercedes-Benz M271: which parts are renewed in a timing chain replacement?
Besides the chain, the tensioner, guide rails and camshaft sprockets are usually replaced, and of the lower parts there may also be something to replace, such as the idler sprocket. The tensioner is worth renewing every time. The timing is finally set according to the marks, and the job can be done at a workshop.