My straight six has 185,000K on the clock.
I drove up to the top of a local mountain and in the car park at the top oil light come on. Tick over presssure dropped the gadge to zero. Did an oil change with 20w 50w and oil pressure was back to normal, very good. Oil pressure was normal for a few months but then suddenly dropped again.
Engine sounds perfect, burns no oil at all between oil changes but the pressure was fine one day then the next very low again. I have changed the oil sender and it still has low pressure. COuld the oil presure releaf value be stuck open? it the pump worn? I have changed the oil every 10,000 since new but I am reluctant to change the pump as it is such a tough job to do. Does anyone know if the pressure releaf value can jam open, is it common for the pumps to wear. This is the third straight six I have owned the other two had over 350,000K on the clock when I sold them and they were still going strong. Another strange thing is the gadge drops to low on tick over then drop to zero, if you wait 10 second pressure comes back to the first mark.
Please help if you can