Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

Running Rough and Blowing Air/Smoke out of Valve Cover

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  #1  
Old 11-17-2014, 03:46 PM
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Default Running Rough and Blowing Air/Smoke out of Valve Cover

I have a 6.5 diesel turbo in my RV that started shaking (sounded like not running on all cylinders) at the end of a trip (right when I pulled into my destination). Oil was blowing out of the valve cover on the non turbo side. Thoughts? Could it be fuel. Bad injector? Strange it started after so many miles. I switched to my 2nd diesel tank right before it happened.

I pulled the valve cover and replaced the gasket (after I had done the RTV thing and didn't give it enough time to cure 20 hrs!?!?). It's still blowing out the sides a bit, but I believe there shouldn't be that much pressure there.

Just strange that after driving so clean it started shaking like that. Oil was low, but I'm not sure if that was a result of what blew out the sides.

Any help is much appreciated as now we are stranded and getting this thing towed to a garage is a major PITA.

Thanks!!
 
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Old 11-18-2014, 05:22 PM
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You are possibly in for some bad news. The cdr died and is blocking the crankcase pressure . The cdr usually only causes a mess somewhere and no real running issues. Now , a blowby mess + running really bad is an indication of some sort of piston failure. A hole in the top of it , cracked piston or rings could have failed. How does the exhaust look? It is totally possible that the two issues are unrelated and i hope that is the case. It sucks being away from home and your ride crapping out.
 

Last edited by emdmechanic; 11-18-2014 at 05:25 PM.
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Old 11-19-2014, 01:24 AM
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Thanks for the input. Today I exchanged out the cdr and resealed the valve cover. I also bled the injector lines per a recommendation from someone based on everything happening right after I switched diesel tanks. His suggestion based on hot return of diesel into a cold diesel tank could have caused moisture or air in the lines. It ran smoother although not a smooth as before. when I sped the engine up to 1200-1500 it smoothed out nicely. took it for a small drive and still had shaking and some white smoke out of the exhaust. then tried to bleed the lines again, although with the turbo on it's almost impossible to reach them all. might have a go at the lines again tomorrow. not sure where to turn next.
 
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Old 11-19-2014, 05:23 AM
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Take the inner fender out on passenger side makes it way easier to get to everything on that side good luck with your truck.
 
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Old 11-21-2014, 11:47 AM
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Failed injector?
 
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Old 11-21-2014, 12:25 PM
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@racer55: maybe.

I did a bleed test and noticed on the 7 that there was little change in the engine rpm and on the 5 it was dramatically different. So, I switched the 2 of them yesterday to see how it affected the same process. (btw they looked like sht ). When I redid the test it ran much worse when I cracked the line on 7 but was about the same on the 5. These things def need to be replaced or cleaned. Still ran rough, so it think I'm at least going to switch that side (1,3,5,7, the side opposite the turbo) and see. Hoping it's not a stuck intake valve or worse.

Comments, thoughts, greatly appreciated.

Thanks!
 
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Old 11-29-2014, 12:57 PM
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An easy thing you could try is to add a double dose of fuel additive/cleaner in the tank. I use Stanadyne Performance Formula in every tank, I can get it at Auto Zone. Power Service is very common at all the parts stores, too.
 
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