Is there a simple test for a broken timing belt?
On many vehicles, removing the oil filler cap will allow the camshaft to be seen. If so, crank the engine and see if the camshaft is turning. If not, the timing belt is likely broken or stripped. Of course this cannot reveal an engine that is out of time due to a slipped timing belt that is still attached. For more details on timing belts, check the AGCO Automotive article All About Timing Belts.
