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Cat Man
Cat Man, Cat Engine Expert
Category: Construction and Road Equipment
Satisfied Customers: 8421
Experience:  I am ASE Master Certified.
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Working on 2002 peterbuilt with c12 it gotg a rough idle an

Customer Question

working on 2002 peterbuilt with c12 it gotg a rough idle an blowing white smoke. i replaced injectors but still doing same thing. some friends tell me it may have a dropped valve. i did add 3 gallons of coolant to it before i put injectors in. what do you think this could be. O an it started this going down road skipping ang blowing white smoke
Submitted: 11 months ago.
Category: Construction and Road Equipment
Expert:  Cat Man replied 11 months ago.

Thanks for asking your question. I will try and help you out.

Yes it is possible you have a damaged valve. To verify. I like to remove the injectors and use a rubber tipped air nozzle to blow air into the cylinder. If a valve is damaged. The cylinder will not hold air and you will hear the air coming out the intake or exhaust.

You could also have a cam lobe failure. Cam lobe failures are common on these engines. You can run the engine with the valve covers off and watch all the rocker arms. If a cam lobe is damaged. One will not be going up and down that much.

Please reply back if you need more help or have more questions. I am happy to assist.

Customer: replied 11 months ago.
Do I need to run overhead on it even though I put back together same way took apart if so what's procedure
Expert:  Cat Man replied 11 months ago.

Yes it's best to run the overhead again to make sure it's right.

Here is the procedure you need.

https://dl.dropboxusercontent.com/u/11922365/1ii.pdf

Expert:  Cat Man replied 11 months ago.

Please reply back if you need more help or have more questions. I am happy to assist.

Expert:  Cat Man replied 11 months ago.

Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.

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