Howdy all,

I just changed my driver's side valve cover gasket on my LG4 305. Reused the cover. I changed over to studs, nuts, and spreaders from the factory screws, and used a rubber gasket. After the engine warms I am getting some slight smoke out of the rear (near the firewall), however, there is still some old oil on the manifold from prior leaking. In your experience how long would it take to burn off the oil still on the manifold? I'm not sure how to tell yet if I'm leaking from the new gasket or not. First time I've done this job. Thanks.

Intake or exhaust manifold?
if it's the exhaust, id clean off as much as you can so you don't have a fire
Oil can also wick up the intake bolts and endup on the manifold.

Exhaust. Agree -- I'll try degreaser and brush/scrub what I can, and hose it off. The passenger side is worse and I'm changing it next. I started with the easier side (driver); the AIR system, EGR, etc are all in my way on the passenger side, going to have to work carefully taking off pieces to get them out of the way.

To answer your question, if the leak is fixed, the oil should burn off of the exhaust manifold after a short drive. If you're still seeing smoke and smelling it, its still leaking.

Quarter car wash

And some SuperClean...

Thanks!