Okay guys I am new to this forum so hopefully I have posted in right thread. A little insight about the truck, I have a 2000 Chevy silverado 4x4 with gen 3 5.3. Just put on3 turbo kit, s475, btr stage 2 turbo cam, btr 660 springs, 7.4 pushrods, arp headstuds, truinion kit, new oil pump, fic 80lb injectors, and Walbro 450 . Whole motor was tore apart 50k miles ago and had new flat top pistons installed, new bearings, and cylinders honed and etched. All new seals and gaskets were put on when I pulled motor out to start turbo build. Has new tci flywheel, circle d pro series converter and new rpm level 6 trans.
Since I have got this build pretty much finished and on the road with a driveability tune I have had an oil leak. I'm getting oil inside the bell housing and getting some slightly from front seal. I have checked not oil sending unit and cam sensor and those are not leaking, I also replaced rear cover with main seal and gasket, it still was leaking. Then I replaced oil pan gasket, and it still was leaking. I am leaning to to much crankcase pressure, since it's blowing it out from what I can tell just the front and rear main seals. I have the pcv system hooked up but I wanted to vent both covers to a vented catch can. I'm thinking and leaning towards I don't have enough ventilation. Am I on the right track? Or no? I want to get this figured out before I go to get the truck tuned.

 

I had an issue with my crank sensor o-ring leaking and making it look like a rear main. Also check o-ring on dip stick.

 

Yea both sensors are not leaking and oil dipstick tube isn't leaking either, it was at first but I fixed that.

 

Clean everything off. Use rags and decreased.
Don't start yet and wait. Check the areas.
If clean and dry start it up. Don't drive it.
Check again.

Oil like water can look to leak from one area and it be completely different.

 

By "PCV system hooked up" do you mean like the factory with the valve cover going to the intake? If so, you need to disconnect that line entirely.

 

+1 with above /\

If you have the factory Pcv hooked up youre pressurizing the crankcase

 

Trick turbo I will, and did when I first put pan gasket and rear main cover back on this it started leaking and is hard to pinpoint looking through bellhousing. It don't seem to leak until driving. Also atomic I had passenger side hooked up and drivers side hooked up to catch can but it was venting then I realized I had it wrong. So I hooked passenger side up to before turbo into air filter, then driver side I put to my catch can and other line to throttle body with a check valve in between. Now I'm to the point of both lines venting to atmosphere and still am leaking oil but I just did this. There still may be some residual oil. Passenger side is just ran with 3/8 hose and venting, drivers side is hooked to pcv valve and ran to catch can then venting out other port. Looking at front of motor, front main looks like it is leaking and running down passenger side of oil pan. And bellhousing is wet and leaves drops of oil for both. Does not seem to leak and drop till I drive it.

 

When you replaced
the rear main seal did you replace the rear main seal cover gasket? Had a similar problem and the rear cover gasket was the problem.

 

I did replace rear engine cover gasket when I replaced the cover, got the new upgraded cover that caked with seal already in it and the new bolts and got a new seal.

 

The throttle body connection even with check valve.
You were not venting enough.
Depending on that connection and the check valve that hose hose might not have been doing anyone but taking up space.

New way you have it hooked up.
Let me see if this is how you have it connected?
Driver sided to a vented catch can.
Passenger side to the front side of the turbo.
Port on throttle. Body and top of intake capped off.