I am working on my 1997 Oldsmobile Cutlass; it is an automatic; 3.1 Liter; with 155000 miles. I recently had a lifter that was sticking and therefore replaced the lifters and had the heads resurfaced. While the engine was apart I noticed excessive sludge build up in the lifter valley and head area. I cleaned the lifter valley and flushed the pan the best I could without removing it prior to putting the engine back together. In attempting to start the vehicle now the oil filter gasket blows off the car. I have tried 3 different types of filters and same result with each. My question is could sludge have plugged the oil pressure regulator? Any help with this issue quickly would be wonderful. Thank You.
You need to remove the oil pan and investigate thoroughly. Check the oil pressure relief valve.
As pressure builds in the oil system, it exerts pressure. A spring-loaded " pressure relief valve" built into the oil pump (or near the pump) opens when pressure exceeds a certain limit (typically 50 to 60 psi) and either reroutes oil back into the pump's inlet or the oil pan. This prevents a dangerous buildup of pressure that could rupture the oil filter or blow out press-fit oil plugs.