When oil is cold it is thicker than when it heats up - I'm sure you know that. One of the most misunderstood things about an engine is the way oil pressure is created inside of an engine.
Oil pressure is NOT created by the pump. It is created by RESISTANCE within the oilling circuit of your engine. The oil pump is a positive displacement pump, meaning is just moves oil from one place to another. The pressure is created by RESISTANCE which is - the size of the openings of the oil passages inside of the engine - the oil clearances in between the bearings, rings, pump gears (etc) - the strength, or tension, of the oil pressure regulator spring - and last but not least oil temperature. However, oil temperature is probably not your problem. Remember - oil is a little thinner as it heats up, and if the resistance is less - like worn out bearings or a broken pressure regulator spring etc. - The pressure will go down.
Is this a new pump? If so, did you change it because of the pressure problem? Also - if new - is it an exact replacement or a so called high volume pump?
Sunday, November 16th, 2008 AT 1:47 AM