Turbo issue - 2004 LB7 with 97K miles

[Mark Rinker]

On my way home with unloaded trailer from Seattle to Minneapolis, started to hear a faint squeal similar to a belt slipping, when under acceleration.

Checked belt/tensioner - no problems. Finally on a steep downgrade I engaged the exhaust brake (not normally used when empty) and the squeal was constant and definately boost related...

With doghouse removed, the squall is unbearably loud. Turbo is functioning normally under moderate throttle but noise occurs under acceleration and activation of exhaust brake. Power and mileage normal, no black smoke even under heavy acceleration with squeal present.

Not sure if its a bad turbo to intake seal or a bad wastegate, but the truck is going in Monday to get it addressed - a smidge under warranty expiration.

[Duramaster]

Hey Mark! Just saw your post on the turbocharger. Sounds to me like it is a burned out exhaust manifold gasket. Use this tool http://www.sears.com/shc/s/p_10153_12605_00945164000P Take the probe end off so that you just have the hose attachment on. Trace the hose around the exhaust manifolds and turbo area. Anywhere there is an exhaust sealing area. Good luck with that.

[Mark Rinker]

It was a seal - as you guessed. They stripped or broke a bolt when disassembling, a new tube/gasket are on order. Warrany will cover the fix.

[Duramaster]

Cool! Hopefully it's not broke down for too long.

[Mark Rinker]

Me too - we are trying to get out of town with a boat today or tomorrow...back to Seattle.

[Mark Rinker]

They fixed the leak mentioned in previous post, only to discover another at the exhaust manifold. Both are now corrected.

Also addressed a small oil leak on drivers side of block. Said it was a block plug (?) that needed resealing - not the oil fill or dipstick tube that I had suspected.

My last smidge of warranty will run out on the next trip to Seattle - so I guess this is the end of the road for cheap fixes. (Although GM extended the injector warranty to 200K and put it in writing shortly after replacing all 8...)

$105.