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BOBBYSS, Master Technician
Category: Chevy
Satisfied Customers: 17284
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Chevrolet Silverado 2500: I have a 2002 duramax 2500 the crankcase

Customer Question

I have a 2002 duramax 2500 the crankcase keeps filling with diesel we just replaced the injectors and new injector lines what else would cause that?
Submitted: 2 years ago.
Category: Chevy
Expert:  BOBBYSS replied 2 years ago.
Hello, my name is***** for the question. If I am not online when you return please give me some time to get back to you. Can you tell me how much you need to drive it before it fills with fuel?
Customer: replied 2 years ago.
I would say approx 250 miles and it fills up and oil pressure starts to drop again pretty fast fuel leak I would say! the truck dosent smoke like it did befor so the injectors fixed that issue but it still is filling the crankcase also no injector sleeves pulled out so we were lucky to not have to replace any of those
Expert:  BOBBYSS replied 2 years ago.
Thank you. If it is not smoking then most of the time this is caused by a compression issue. It may be on one or multiple cylinders. Due to how bad it was before, the oil being washed from the cylinders may have causes some damage to the walls and now you have a compression issue.
Customer: replied 2 years ago.
The runs fine no issues a compression issue would cause smoke? Correct aren't we talking like a return line or something that may leak ?
Customer: replied 2 years ago.
And a compression problem wouldn't cause the crank case to fill?
Expert:  BOBBYSS replied 2 years ago.
Most of these parts would cause external leaks. If it is getting into the crank case then it is either due to too much fuel still coming from the injectors or it is not burning all of the fuel off. Is the check engine light coming on?
Expert:  BOBBYSS replied 2 years ago.
When you pull the valve covers is there any sign of tracking on the head from fuel such as clean areas?
Customer: replied 2 years ago.
I know there was no signs as far as I know when we remove the heads the only thing I can think of would be a high-pressure fuel line leaking but we put new ones in and also a return line with leak into the valve cover but I replaced the seals? Possibly a shaft seal on the high-pressure fuel pump Can I test the return lines? By using a vacuum pump
Expert:  BOBBYSS replied 2 years ago.
It is better to pressure test them than to do a vacuum test, but you can do it that way.
Customer: replied 2 years ago.
So in your opinion what do you think? I honestly don't think it's compression because of how well the truck runs and how there is no smoke from it if there's any loss of compression usually diesel motors smoke
Expert:  BOBBYSS replied 2 years ago.
I don't think it is compression either at this point. It would not be running well if it was. I am suspecting a bad connection on one of the lines or a return line itself.
Customer: replied 2 years ago.
What is needed to do the test on the return lines just a vacuum pump? And also if the high-pressure injector lines are leaking wouldn't it be coming out of the connection on the top of the valve cover ??
Expert:  BOBBYSS replied 2 years ago.
If a vacuum pump is what you have that will work. Pressurizing the lines is better, but that is much more expensive equipment. As for the pressure lines, they can leak on the injector side.
Customer: replied 2 years ago.
Okay well I'm going to pull it apart test it and run it with the valve covers off to try to find the leak what do I can add to the fuel?
Customer: replied 2 years ago.
Okay so today I pressurize the entire return system and I can hear some air blowing out of the return fittings that should be a problem correct we're going to get new return lines and seals how long should the system hold pressure for?
Expert:  BOBBYSS replied 1 year ago.
If there is air coming from the fittings then that is more than likely the issue. I usually add some soap to it so I can see the bubbles. You should be fine after replacing those though. Let me know if you need more help.
Customer: replied 1 year ago.
Ok we replaced the lines and seals it no longer leaks it held 15 psi and put it back together I really hope it dosent leak but if it does its the highpressure fuel pump how often do you see that??
Expert:  BOBBYSS replied 1 year ago.
I do not see the high pressure pump fail very often on this engine other than losing pressure. Rarely if ever an external leak. I hope this takes care of it. If you need anything else please let me know.