Nissan Repair: pressure in engine biock, piston rings, oil cap

Question
nissan pulsarQ 1991 engine seems to build up pressure in the engine block forcing the oil out of the oil cap. why? and how do i repair it thanks sam

Answer
Sam,

Either you have a bad converter on the exhaust blocking the flow and causing backup into the crankcase or you have bad rings in the engine.  Disconnect the converter and see if the car runs properly and the oil stops backing up and out the oil cap.  If this does not work then you know you are in for a rebuild of the engine to replace the piston rings.