remove the intake manifold, its screwed in right in the back, cant miss it. Sounds probably for you leak

 

Just a thought...

When you built the forged motor, did you use a LS1 crankshaft or one from a manual tranny truck? My LS1 crankshaft has a 1/2" press-in oil plug about an inch into the crankshaft, right past where a manual car would install a pilot bearing. It could be leaking under boost and it will dump the oil into the inspection cover jsut like a rear main seal problem.

Another thought is that it could be the rubber seal on the white oil "dumbell" that you insert before you put on the rear cover. Could have torn but only dumps under boost.

I had the exact same symptoms when I installed my turbo kit. I even went to a coin-operated car wash, powerwashed underneath the truck and could cover the crossmember/tranny/frame with a ton of oil just by getting on it a couple times on the 10 minute drive home. In my case it ended up being the dipstick tube. It looked fine but it was not fully seated. I pulled it out, put some RTV around it and "tapped" it in till it seated. Went back to the car wash for round 2 and not a drop on the way home. The dipstick tube may be worth another look.

Best of luck with your problem. Oil leaks suck.

 

Previously owner didnt have any leak that I know of. Im thinking I need to do a comp check, its easy enough, and then if that seems well, remove the tranny again and inspect all the *** end. And I think this was an 05ish stock motor

I did recheck the dipstick yesterday, and it was very dry, not leaking.


Something I forgot to mention, I found a hairline crack in the Al rear cover when I did the rear main, so I replaced it with the cover off my 2004 4.8. Is there a difference in the cover I could have missed or messed up?

As well as, I dont think the motor is hurt, it runs strong for the crap tune in it, ( lots of fuel not much timing) and doesnt seem to be noisy or different sounding.

 

Sounds like the cover has been off and if the cover was not installed correctly it can cause the the rear main to be off center with the crank thus pushing oil out and it would not take much. Also did you replace the gasket. Napa makes a dye for the eng,trans and so forth uses an ultraviolet light to be seen works good for those pesky oil leaks. I would suggest that you clean it up again and jack it up and get under there and look around with it running and a buddy on the pedal cause that sounds like allot of oil not to be seen with the naked eye. If you can pull the trans back and do it all at once would keep you from cleaning over and over. Good luck with the search and let us know what you find for future probs.

 

check out this thread i found on tech. Looks like the seal needs to be installed backwards, well at least it fixed some of the issues people were having on tech...

https://ls1tech.com/forums/generatio...l-install.html

 

mother Fer.

there was a not with it that it was a backward seal, as IIRC they way it was now designed the "lip" is facing towards the tranny, so anything other than vacuum in the crankcase would easily make it leak. hmmmmm.

 

I believe you owe me a case of beer.... I prefer Shiner Bock...

 

The seal that they are talking about sounds like the teflon seal that comes with the plastic install tool if so they are crap I hate those things. Just get the old style at azone or somewhere like that if they are out there.

 

Altho i never drove it with the open turbo headers, during some 6k rpm free revs, without the turbo hooked up (crossover removed) it wont drip a drop.

 

Yeah get Shiner so I test atleast 6 of them to make sure they arent poisoned