It's an L98 with 1500 miles on it. Started it up yesterday and noticed smoke pouring out of the valve cover breather. This could only be from severe blowby b/c of bad rings, right? I just want some input before I pull the motor out. Going to do a compression and leakdown test sometime this weekend. Any advice/ideas please post!!!

 

forgot to mention, nothing coming abnormal coming out the tailpipes.

 

It can also be a bad intake gasket (leaking from the exhaust crossover passage into the crankcase) or valve guides.

 

anything in particular I should be looking for during the compression/leakdown tests to narrow it down?

 

Those tests will only show bad rings, bad valve seats (not seals or guides), or bad head gaskets. They will not show the other possible causes. It is also possible for the compression rings to be fine, i.e. no compression problems, and the oil rings to be inoperative (oil burning). So, all in all, don't expect conclusive results from those tests.

 

Ok, then I guess my question should have been how do I narrow it down to intake gasket, head gasket, or rings? I don't want to invest time and $$$ into fixing the intake gaskets and end up pulling the motor out anyway, 'ya know?