The most common cause of low oil pressure is worn engine bearings. Next would be oil that is too thin due to being the wrong viscosity for the engine or it's diluted with gas from a previous running problem. The first thing is to have your mechanic connect a mechanical oil pressure gauge to verify the pressure really is low. If it is not, suspect the oil pressure sending unit.
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Sunday, July 21st, 2013 AT 1:27 PM