Discussion Forums : Technical Help and Advice

the oil pump is mounted on the side of the engine, pipe goes down into the sump from suction side of pump,when starting from cold it takes a very long time for oil light to go out - I have looked at the pressure relief valve - is there a non return valve between the pump and sump? I think the oil is back draining back to the sump when the engine is switched off, if the oil is warm it isn't a problem but cold it is a problem - I have cranked it over with the filter off - these filters are inverted to normal filters in that they face down - I think if the oil is cold it has to overcome the pressure drop of the filter, the pipe it travels up to get to the pump and result is lack of oil to the engine? if I am right can I solve this problem?? any suggestions or advice offered is greatly appreciated - many thanks