my car leaks oil like crazy after i park it and turn it off but i cant tell were its coming from. Is there a comon place were lt1's start to leak oil?

 

Common places
1. rear intake manifold oil leak. Very common (fixed mine 3 times before it took) Feel behind the intake (make sure the engine is cold!!) for oil leaking from the back if it is there are a few online guides on how to fix it.
2. rear main seal. I've also had this leak, caused the clutch (M6) to start slipping, had it replaced when I replaced the clutch.

These are the two that I hear most about, that's not to say your leak could be something else... but these are a few places to start looking.

 

In service we used to add a chemical to the oil that would glow under a special blacklight. That's how we could tell the new oil from the old. Any dealership can do this.

If you're looking to find it yourself and you're in a pinch, try throwing baby powder in oil covered areas, it will stick to the old oil, and new oil jump will show new lines in the powder. That's the ghetto version.

Hope this helps,
-Christian