Engine/Transmission (1998.5 - 2002) Valve Lifters or Exhaust Manifold Leak?

[rootmanslim]

I know real trucks rattle BUT. My 2001 with 73 K on the clock has a noise, that were it a solid lifter 327 Chevy, I would say was one solid lifter needing adjustment. But my 01 doesn't have solid lifters and, according to the factory manuals I bought, the tolerances for lifter adjustment is quite wide. My second thought was an exhaust manifold leak. As the truck gets warmed up (I am at 7700' up in WY), the noise lessens but never really goes away.

Mileage remains at 22 mpg+ (3. 55 rear and 19. 5" Rixons)



Any diagnosis tips? I know the manifolds have a rep for cracking and I thought hydraulic lifters were self adjusting.



I run Rotella 15-40, change oil & filter every 3K, no oil consumption between changes.



Thanks!

 

[Bob Cochran]

I think you will find the lifters are solid not hydraulic so it could be a lifter out of adjustment. When the header is cracked the ones I have seen is obvious. A bad injector maybe? Somebody will chime in with more help I am sure.

 

[fox]

I wouls first thimk it would be a cracked exhaust manifold. But it is easy to pull the valve cover--the gasket is reusable--and check the valve adjustment. It needs to be done every 50,000 miles in my opinion, rather than the 100,000 mile recomendation.

Intakes at . 010 with a + or minus of . 002

Exhaust at . 020 with a + or minus of . 002.