LB7 turbo to manifold gaskets

[Mark Rinker]

Have a whistle from the turbo area on deceleration with exhaust brake engage - 2004 C4500 LB7.

This is the second time around for this fix, first was under warranty - this time will be on my dime so I want to get it right!

Anyone know of a better set of turbo to manifold gaskets? Obviously, mine aren't holding up under the rigors of heavy towing and the factory C4500 exhaust brake's peak backpressure. I have experienced (created) both failures, ironically on the same downhill grade (Monteagle, TN on the way to FL with heavy boat) always with the exhaust brake on.

Need...MORE GASKET... (...or maybe less backpressure?)

[JohnC]

Turn the radio up.

[Mark Rinker]

Turn the radio up.

Thats what we have been doing!!!

Seriously, its really only an annoyance on braking, but eventually, it starts doing it slightly under heavy acceleration as well. Same leak, same sound, different volume...

Based on this description, do you think it would be the gasket at the crossover, the base of the turbo to intake, or...? I have three part numbers that were replaced the first time around. I think they took the 'shotgun' approach, but the one that blows out is the same...same sound, anyway...

[JohnC]

If it's under braking I'd expect it to be on the exhaust side.

Turbo inlets and outlets are standard sizes. If you can find the type of gasket that is thin stainless with a raised bead ~ 1/32" radius around the sealing surface, get 2 and nestle them together. They're blow proof and burn proof (for the most part...)