[97Formula]

Originally Posted by Pampered-Z

Has the car always been run on Mobil1? Did you switch from standard to synthetic? You might have caused some slugged to break free and it's causing a clogged lifter and it's collapsing, why adjusting the values cure it slightly, slightly clogged oil pickup, or something to that effect.

Start by changing the oil and filter. 5W is too thin for an LT1.
Get the recommended GM filter, WIX are good too, but the GM at Walmart is probably cheaper. Don't use the other brands, that could be part of your issue, LT1s are odd with filters? Move up to slightly thicker oil 10-30 or 10/40. I would do changes ever 500 miles and see if it gets better.

I've been using Mobil 1 since 6000 miles. I've used K&N and Napa (WIX) filters, not a fan of the AC Delco PF454 as it is half the size of the K&N and Napa.

It's in the shop again as I've developed an even louder tick at 1900 rpm (no tick at idle, and the tick at 1900 gets quieter as it warms up). Still have cold oil pressure at 60 psi, warm/hot at 15-20 psi. They're gonna start diagnosing.

Also just found out my head gaskets are leaking! However the car never overheated, still running cool, etc. I asked the shop if they saw cross contamination with the oil/coolant they said no (oil looks normal, not milky, and is still full). So it looks like the block is coming out...