Review on Melling-10295 Oil Pump - Wet Sump, Internal, Standard Volume & High Pressure for GM LS-Series - Each by Mike Weaver

I installed this high mileage (195,000) 5.3 that had a damaged o-ring on the original pump suction tube. Before replacing the pump and o-ring (failed suction o-rings are the number one cause of low oil pressure in the LS) I got a low oil pressure warning on cold start. Now I have 50psi on start and when hot the oil pressure stays at 40psi. I figured I could also upgrade and replace the oil pump that does the o-ring work and am happy with the restored oil pressure provided by the Melling pump. A side effect of raising/restoring the oil pressure in my 5.3 with this pump resulted in oil being forced through the PCV into the intake manifold, this was an easy problem to fix with the Moroso oil separator, be aware of this especially if you have an older LS with no upgrade PCV systems (mine was upgraded but still needed a separator after installing this pump) you may have the same issue. If you smell burning oil you need to install an oil separator ASAP or you will damage your catalytic converters and end up with a P0420, P0430 or both. Spring. Instead of stripping the connector, I left the included compression spring in the pump.