My dads 2001 Sierra C3 with just over 60k miles on it has developed an oil leak. It is leaking from the rear of the motor somewhere, above the oil pan. Oil is all over the pan and such, and dripping quite a bit. The dealer said something about it maybe being a rear main seal, or maybe it is leaking at the rear of the intake. Anyone have any insight on this? Thanks for any help.

 

Check the valve cover gaskets and/or tighten up the valve cover bolts. Then check the plate where the oil cooler lines screw into on the block above the oil filter, those sometimes like to leak.

 

The Only Way To Really Tell Is To Pull The Trans.it Can Not Be The Intake.i Have Seen The Vally Cover Leak But That Could Be,chekc The Valve Covers Like Neil6.0 Said.u Can Also Pull The Cover On The Trans Bell Houseing And Inspect.

 

That plate by the oil filter is likely,rear main seal leaks are rare,if they do leak its because something else went wrong like worn mains or the rear main Brg.not likely though.

 

I'll take a pic of the underside tonite, its all OVER the bottom of the engine.