1995 Sonoma LS

[leegreen]

4.8 started having nasty lifter rattle after warming up.
Messed around the last couple weeks swapping some know good lifters and replacing questionable rocker bearings with a trunnion kit. That made it somewhat quieter but there was still internal noise.

Pulled the motor last weekend and found this

Oil pickup o ring failed after around 15,000 KM. Pump sucked in some air once motor warmed and lifters don't like foamy oil.

Engine back in with new o ring and all is well.

The failed o ring came with the aftermarket pan and pickup. Suggest anyone contemplating an LS swap get a brand name o ring and throw away the anonymous one that came with your pan.
Felpro 72401 is what I used. same as GM12584922 Red

(there is also a smaller version on earlier LS, GM12557752 Blue)

re&re engine and trans to get to a $5 o ring what fun.