1. On a cold engine, unscrew the oil pressure switch and screw in a verified pressure gauge instead.
2. Measure the oil pressure at idle and at the speed indicated in the Technical data (To do this, connect a tachometer), compare the measured values with the standard values. Check the pressure on a cold and warm engine.
3. If the pressure is low, then compare its value for a cold engine with the standard one. If the oil pressure on a cold engine is above normal, and on a warm engine it is below normal, then the engine is filled with oil that does not correspond to the recommended viscosity. Change oil and check pressure again. Low oil pressure indicates worn engine parts or a failed oil pump.