2000 GP GT 190K miles
Original oil pump, valve train, main bearings and heads.
Synthetic oil only with Mobil 1 filter.
I recently noticed the oil pressure light coming on sometimes at idle. The bottom end was getting noisy as hell. After pulling the oil pan I gauged the rod bearings. None were less than 0.005" clearance but the journals were all 2.250" and nice and smooth (yea for synthetic oil!). Some of the bearings were worn through to the backing. I replaced the rod bearings and put everything back together. I thought this would take care of my oil pressure problem. The bottom end is now as quiet as a church mouse. It runs like a bat outa hell!
Now, after 3500 miles of driving since replacing the rod bearings, I've noticed a tremendous amount of noise coming from the valve train at idle and the oil light still comes on.
Question
Could the valve train be starved for oil due to the oil pump or maybe loose main bearings? Maybe the lifters aren't pumping up; dropping the oil pressure? I haven't checked the oil pressure yet. Where should I start?
