Bent valves can occur as the by-product of a timing belt failure, as the valves depend on the timing system to let them open and close without accidentally striking the pistons, according to AA1 Car. Compression testing to check valve function can confirm this problem.
If a timing belt breaks while the engine operates, the driver should ask the repair techs to check for bent valves while they replace the belt. Symptoms of bent valves include a lack of engine compression and telltale scoring on the pistons, according to 2 Car Pros.
Auto repair shops commonly perform a compression check to diagnose bent or otherwise impaired valves. This procedure involves first removing the spark plugs and disabling the ignition coils, then attaching a compression gauge to a spark plug hole while cranking the engine, according to AA1Car.
The compression gauge should indicate 140 to 160 lbs of pressure across multiple readings. Low or inconsistent compression readings indicate a problem with a piston ring or cylinder rather than a bent valve. An engine with consistently low or nonexistent compression readings suffers from bent valves.
