When the engine presents no oil pressure, check for the following, as necessary:
- Low oil level in the crankcase.
- Broken oil pressure gauge or sender.
- Blocked oil pump passages.
- Blocked oil pickup screen or tube.
- Malfunctioning oil pump.
- Sticking oil pressure relief valve.
- Leakage of the internal oil passages.
- Worn (loose) camshaft bearings.