So I’m putting the car away for the winter and decided to pull the motor to replace the oil pan gasket. It’s leaking where it meets the rear cover. Rear cover gasket and main seal is bone dry.




Motor is a forged rod/piston ls3 block making near 900 rwhp with a procharger.

Runs great only reason I pulled it is to do the oil pan gasket. I bought the short block then assembled the long block and installed it about this time last year.

When I took off the intake I noticed it had a lot of oil in it. Then I pulled the plugs and they all had oil on the threads. So now I’m thinking blow by and crank case pressure may be why my gasket started leaking.

I was running a small MM catch can with one way valve and -8 line on passenger valve cover and small filter on drivers side valve cover. Catch can had a one way valve so it would not boost the crank case.

Im thinking I will try a large breather on passenger side. Vent valley cover to passenger valve cover and run a vacuum line from drivers side valve cover to intake before procharger this time around.

I don’t put a lot of miles on the car and change oil frequently, but even with the leak and all the oil in the intake it never was enough to show up on the dipstick and it doesn’t smoke. Cooler days I’d get some steam and water drips until it warmed up, but that is all. Motor runs so good I was shocked to see the intake and plugs so oily.

Any input? Normal for a high boosted LS or anything I should do while the motor is out and the car is parked for the winter anyway?