Is the engine ruined if the timing belt breaks?

Not always, but a broken timing belt can ruin an engine, especially if it is an interference engine. Most German auto engines are interference engines.

In an interference engine, the pistons and valves share a very tight space at different points in the engine's rotation. When the timing belt breaks, the camshaft stops turning in sync with the crankshaft, and pistons may hit open valves. The result can be bent valves, damaged pistons, broken valve guides, cylinder head damage, or a repair bill high enough to make complete engine replacement more practical. In a non-interference engine, the vehicle usually stalls and will not restart, but the risk of internal damage is lower. Do not keep cranking the engine. Have the vehicle towed and inspected before attempting to restart it safely to avoid further damage.

If you have timing belt problems in Ann Arbor or nearby, call Stadium Auto Service at (734) 369-6787, make an online appointment, or visit the shop. We have technicians who specialize in timing belt diagnosis and repair exclusively on Audi, BMW, Mercedes-Benz, MINI, Porsche, and Volkswagen.