Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello, since you confirmed that the pressure is dropping, then returns using a mechanical gauge, I would believe the pressure regulator in the oil pump is sticking. It is designed to control the oil pressure as the engine is at different rpms.As the pressure is increased it will open to dump pressure, then is supposed to close to let the pressure return. If the valve sticks when open,it will not permit this. I am sending an illustration of the pump.You may either remove the pump, disassemble and clean the valve,or due to the labor involved that requires removing the oil pan,it may be best to install a new pump.If you had worn bearings,the most common cause of low pressure,it would cause the pressure to drop when the engine was warm,and would not return until the engine was allowed to cool.Thanks for using Just Answer,Jerry.