Do they inevitably fail after several years...warping or whatever...or is just something you can't predict?

 

they are generally one of those things that don't fail unless they are made to fail.

 

Thanks...anyone else? A friend has a 98 one ton with a leak...at about 100k miles.

I saw a V-6 that had a really bad one...steam coming out of the tail pipe and the radiator water level would drop when the engine was revved.

 

that's a whole different thing. the L30, L31, and L35 engines all commonly have intake gaskets that leak.

 

OK,so it's more of a problem on the 6 bangers.

 

No its a problem on the 1996-2000 Oldbodystyle trucks with the 350 and 305 GEN 1-E V8s (L31/30) as well as the V6's.

tell your friend to go get the newer GM gaskets and only torque it to 11 lb/ft.

peace
Hog

 

The only real problem with the Gen-III manifold is that air into the front impacts the rear of the plenum causing higher pressure to the #7 cylinder intake port. The extra air makes that cylinder burn lean under high-power applications (Boost). The resulting lean condition melts the piston. It has happened to dozens of people on this forum.