How are Camshaft issues diagnosed?
Since the camshaft can fail by seizing or by flattening out a lobe, the technician will either receive a vehicle that runs terribly and misses on one or more cylinders repeatedly. If the engine will not crank or start, the technician will notice that the starter engaged with good battery voltage, but could not turn the engine. The engine will be turned by hand, and the technician will find they can not turn the engine. At this point, the engine is declared seized, but removal of the timing chain or belt must be done to verify if the camshaft or crankshaft has seized. If the engine cranks, but cranks quickly and without pulsation, the timing belt or chain will be inspected. If mission, the camshaft will be turned by hand, but will likely be seized. Finally, if the vehicle runs rough, the technician will begin by reading on-board diagnostic trouble codes, will find misfires on likely one cylinder, and will begin diagnostics by testing several other components. The ignition coil, spark plug, fuel injector and fuel injector seals will be tested. Afterwards, engine vacuum leak testing may even be conducted before the camshaft is suspected of failure. Once these items have been ruled out, the camshaft valve cover will be removed, and the camshaft will be directly inspected, or the lift of the rocker arms will be checked with a dial indicator. Once tested, it will be obvious that the camshaft lobe is no longer lifting the cylinder head valve enough to allow for proper operation.