GM LS OIL PRESSURE PROBLEMS
We had rebuilt a customer’s 5.3L GM engine but they were still complaining of low oil pressure at idle. We sent them a new oil pump, but it still was low, about 17lbs at idle. We learned that there was a second oil pressure relief valve in the oil pan, just above the oil filter mount. We had not seen the pan during the rebuild. They replaced the valve and oil pressure jumped to 30 lbs. Our 2010 5.3l pickup with Active Fuel Management took part #12608835. I understand there are additional part numbers for different years and applications. This part is often overlooked during rebuilds and I’m sure many repairs have been done, when this $10 part was the problem.
Harry’s Machine Works