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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29516
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2005 Chevy: Duramax LLY, changed head gasket..Blown head gasket

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2005 Chevy Silv. Duramax LLY, changed head gasket on right side, because of pressure in water system. Blown head gasket. on rear cyl. back together starts and runs, but will not go over 2000 rpm in gear, blows black if you try to accelerate.
Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.
What codes are set?
Did you check the charge air cooler lines and the turbo connections?
Customer: replied 6 years ago.

Cam, Gm Tech

This morning started truck left idle for a few minutes then drove down street with no apparent problem, trans was not in a limb mode. seem to run ok a little sluggish.

stopped after mile and then restarted and proceed another 4 miles shifted OK thru all gears. Picked up a fuel filter (WIX 33960) and new air filter to change. came back to shop changed fuel filter and air filter, sprayed MAP with a cleaner. finally got fuel back in system and started when for test ride and it acted like it did last evening. went into a limb mode and proceed to blow black smoke out tail pipe, drove approximate 1/4 mile returned to shop no codes set. motor idles smooth will free rev to 3500 blow some extra smoke. {Yesterday afternoon there was a P0700 set. but it got cleared.}

Disconnected batteries for about 5 minutes and reconnected, did another test drive. same problem.

this problem appeared after we removed right head and replaced head gasket that allowed pressure to enter the water system. (Had a broken fire ring on number 7 cylinder) which pressurized the system. Since head gasket has been replaced and running of motor there is "no" pressurizing of water system. Top radiator hose is in a relaxed state after motor cools down. Problem solved. But now we have a fueling problem, Have checked the wire harness at alternator for bare wires OK.

Have not checked #2 or #7 injector wire harness.

May have to go to a dealer and have service mechnic check system with a Tech 2?

hoses and clamps to and from inter cooler are tied and in place. clamp at input to turbo seems to be in its proper place. Thank you for your help, I'm not at a computer 24 by 7

so bear with me computer is at shop not at home. will check for answer or suggestions in trying to resolve this problem.


If the only code was the P0700 then all that means is there is a code in the transmission computer.
If you had problems with 2 and 7 you would get codes like P0202, P0207, P2146 and P2149.
Did you get all the grounds cleaned?
Does your scan tool show balancing rates?
Customer: replied 6 years ago.


No scan tools does not have that function. Do not have codes that point to 2 and 7. What grounds are you refiring to?


All on the engine that you may have touched. What I am suspecting is that the lines had some debris in them that caused this. Balancing rated would show if any were low or high.
Customer: replied 6 years ago.


Ok It may possible that the 4 injectors and lines that I remove could have got some dust or dirt in them. Does that mean I will have to remove injectors and send them out and have them refurished. Thats after I have balance check done. What scan tool would I need to do a balance test?


Any advanced scan tool should be able to do this.
It is possible and they may need to be sent out, but lets look at the rates first. Why spend money we don't need to.
GM Tech (Cam) and other Chevy Specialists are ready to help you
Customer: replied 6 years ago.


Have to apologize that I didn't get back to you.

Was unable to find the problem last Saturday. came back on Sunday afternoon and reread your suggestions. said check air charge lines!!!!!!! so proceeded to disconnect

hose clamp before the intake. started to remove hose and then it fell away. Looked and saw that the pipe had been forced out of the hose on the exit of the inner cooler.

Being a very observant individual, I reattached pipe and clamp. Test drove truck, every thing was back to normal. I guess the reason I didn't see that the pipe had slip out it is below the air box and is difficult to see. plus i was thinking that it was something to do with the injectors or ECU.

If there is a next time have to remember to check the simple things first

Ran truck this past week with "no problems."

Thank You


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