Valve Train Analysis - Engine Running

Valve Train Analysis - Engine Running, Valves and Cylinder Head
^ Check for plugged oil drain back holes.
^ Check for missing or damaged valve stem seals or guide mounted valve stem seals.
^ Check for a plugged oil metering orifice in the cylinder head oil reservoir (4.6L engine only).

If insufficient oiling is suspected, check oil passages for blockage, then accelerate the engine to 1,200 rpm with the transmission in NEUTRAL and the engine at normal operating temperature. Oil should spurt from the rocker arm oil holes such that valve tips and camshaft roller followers are well oiled. With the valve covers off, some oil splash may overshoot camshaft roller followers.