grandsub

Something I learned the hard way. On my '05 Suburban 5.3 230k miles. Oil pan gasket leaking badly so I dropped the cross member, removed all the oil line supports and the oil level indicator wire, and the bolts that held the cast aluminum pan to the motor and the transmission. I replaced the oil pump suction line O ring, cleaned the engine surface (best I could see from lying on my back under the car), cleaned the oil pan, riveted a new gasket to the pan, put RTV at all four corners of the engine (joints here of engine to timing cover in front and bell housing in rear will leak without RTV) and bolted the pan up. Next day I looked at it and oil was everywhere, and the pan was cracked all the way from rear to almost front of the pan on the driver side. I ordered a new pan for about $90, and cleaned the engine surface again using an old wood chisel. Got all the RTV off and while doing so I tried to remove some from 2 holes where the oil comes in and out of the filter. Surprisingly as I worked hard to clean that surface the surface fell off. It was a piece of the original gasket I had not seen either the first time or the second time in cleaning the engine gasket surface. That little corner piece of gasket with two holes and O rings is attached to the new gasket in the corner (and was to the original gasket), but it came loose from the original gasket instead of coming with the gasket down from the motor. If you are doing this job regularly you will know that. If it's your first time to have to do this, you may miss it and it will cause the cast aluminum pan to crack as you tighten the bolts,. So, look at your new gasket and make sure the old one you remove has the little corner piece with the two holes still attached to the gasket and not stuck to the engine, If you are working with the car on a lift, you may have good enough natural lighting but I did not see it. I read many articles and watched lots of videos and this was never mentioned, but these leaks on 200K plus engines are quite common. So, learn from my mistake. You're welcome!

Senolin32

At least you found the problem bud!

I've done this on a tired day with an oil filter LMAO. Old oil filter's gasket got stuck on and i didn't notice. Got the new one on, started the truck and sure enough oil just going everywhere! This is why I always, always check for leaks before driving off. Ya never know, even on simple jobs.