Must I change timing belt on my VW Passat?
Dear Neto,
I own a VW Passat 1.8T. The car runs quite rough despite the fact that I have changed most of the faulty sensors after diagnosis. My mechanic now says I have to change my timing belt because it is stretched.
How true is this yet the tensioner pulley takes care of the slack in the belt?
Paul.
Dear Paul,
I agree with your mechanic on this one. It is a common assumption that the toothed rubber belts on Passats do not stretch.
The fact is that they do, thereby mismatching camshaft sensor signals to the crankshaft sensor signals which are responsible for ignition and injection timing.
In the cases I have come across, it is usually registered as a signal range performance problem simply because the crankshaft and the camshaft are not rotating at the correct speed relative to each other.
Passats are so sensitive that even a slightly loose timing belt tensioner will change the way the engine behaves. The timing belt must be changed once such problems have been experienced.
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