Fuel in crankcase, lots of fuel!

[rbouvier]

I have an 03 2500HD with 119k. I had smoke and some fuel in the oil, roughly a gallon every 400 - 500 miles.

I had all new injectors installed, cups, lines and even glow plugs. I had an airdog 4g 100gpm lift pump installed at the time of injectors. I had a massive oil/fuel leak, over 2 gallons in 40 - 50 miles (crankcase was full and I drained around 5 gallons). It seemed to be leaking from the front seal. We figured CP3 so that was changed also. I did an oil change and drove it 50 miles and the crankcase is full again and leaking from the overflow/vent tube.

I am at a loss! What else can it be?

Any help would GREATLY be appreciated.

Thank you in advance.

Rick

 

[RMJ_LB7]

lines more than likely were not installed correctly. I know a guy that just got injectors installed on his LB7 from a local well known shop and had the same thing happen. I believe his was his return lines.

 

[rbouvier]

lines more than likely were not installed correctly. I know a guy that just got injectors installed on his LB7 from a local well known shop and had the same thing happen. I believe his was his return lines.

Thank you for the response.

How much fuel goes through the return line? Could they dump enough fuel to fill the crankcase in about an hour and a quarter?

Before I had him change the CP3, I ran the lift pump without starting the engine and it was pissing fuel/oil from the area around the lower pulley, now it's the breather.

I can tell you that it ran okay and smooth.

 

[TheBac]

Whatever you do, stop driving the truck. Have it towed back to the shop.

Where did you buy the injectors?

 

[rbouvier]

Whatever you do, stop driving the truck. Have it towed back to the shop.

Where did you buy the injectors?

I bought the injectors from diesel logic, I regret it. I sould have been better off buying from Extreme diesel or Lincoln diesel, both of them have been phenomenal. I plan on letting it idle for 10-15 minutes without the lift pump connected, let see if I get dripping. I'm thinking that if the return line gets disconnected and pressurized, it should be easy to see if it's the return lines. I plan on changing the oil before I drive the mile to my shop that did the repairs.

 

[slowlml]

Hate to say it but being where the injectors are from i wouldnt completely rule out that its the injectors. Heard of guys having bad ones right out the box. This is how i do it.

https://www.duramaxdiesels.com/forum/threads/lb7-return-line-leak-test.75913/

Really good thread with pictures.
Can also google "lb7 mighty vac test duramaxdiesels" and should find another thread on it using one of those.

 

[rbouvier]

I bought the injectors from diesel logic, I regret it. I sould have been better off buying from Extreme diesel or Lincoln diesel, both of them have been phenomenal. I plan on letting it idle for 10-15 minutes without the lift pump connected, let see if I get dripping. I'm thinking that if the return line gets disconnected and pressurized, it should be easy to see if it's the return lines. I plan on changing the oil before I drive the mile to my shop that did the repairs.

I was thinking of doing this myself. I didn't think I needed to pull the line off the CP3, what is the reason? I have several compressors. One can be regulated down to 5psi. I was going to p
just pull the return line and pressurize with 10lb psi and listen to see if I hear anything.

Hate to say it but being where the injectors are from i wouldn't completely rule out that its the injectors. Heard of guys having bad ones right out the box. This is how i do it.

https://www.duramaxdiesels.com/forum/threads/lb7-return-line-leak-test.75913/

Really good thread with pictures.
Can also google "lb7 mighty vac test duramaxdiesels" and should find another thread on it using one of those.

 

[2004LB7]

Many will install the new injectors and return lines, high pressure lines, etc and run the engine for a bit to see if there are any leaks. Most of the time an engine making oil is from a leaking return line connection on the injector but can also be a cracked injector body or a leaking shaft seal on the CP3.

Leaking return lines can happen from not torquing them down enough and crushing the washer properly. It is also made worse from not clocking the injectors over to the right when finished installing them, when the high pressure hard line is tightened up it puts a lot of force on the return lines and if they are not sealed right they can start to leak.

 

[LBZ]

Was the problem there before the injector swap? If not, I’d be leaning towards a return line more than anything. This is the most common problem. If they get tweaked they can crack and leak. And the seals are a bit flakey at times. After that I’d be looking the high pressure side.

If it was my truck I’d pull the high pressure lines off one side, remove the rocker cover and reinstall the high pressure lines and start it and check for leaks. Then go to the other side. If you don’t see anything it’s likely going to be an injector and lastly the cp3 shaft seal.

EDIT: Reread the OP post. I’d definitely be looking at the return lines and high pressure lines if they weren’t replaced.

 

[Stingpuller]

Pull it apart and check the return lines for a loose bolt or missing seal. if thats good then you just found out why you never buy cheap injectors.

 

[fl0w3n]

Many will install the new injectors and return lines, high pressure lines, etc and run the engine for a bit to see if there are any leaks. Most of the time an engine making oil is from a leaking return line connection on the injector but can also be a cracked injector body or a leaking shaft seal on the CP3.

Leaking return lines can happen from not torquing them down enough and crushing the washer properly. It is also made worse from not clocking the injectors over to the right when finished installing them, when the high pressure hard line is tightened up it puts a lot of force on the return lines and if they are not sealed right they can start to leak.

Never thought about clocking the injectors. I don't recall a ton of slop between the body and the hold down, but on the times I've done them I wasn't specifically looking for that either.

By clocking to the right, do you mean a clockwise twist?

I'll have to remember that for the next time I do LB7 injectors

 

[2004LB7]

Never thought about clocking the injectors. I don't recall a ton of slop between the body and the hold down, but on the times I've done them I wasn't specifically looking for that either.

By clocking to the right, do you mean a clockwise twist?

I'll have to remember that for the next time I do LB7 injectors

It may not be highly important but the hard high pressure lines torque down pretty good on the injectors, so then putting the returns on, it they aren't fully sealed and tightened up then when the high pressure line is installed it could tweak it over just a bit and cause a leak. There isn't much play in the hold down bracket but I like to twist the injectors clockwise however far it will go before installing the return lines and double checking them before putting the cover on. It's just another item to help prevent leaks

 

[fl0w3n]

It may not be highly important but the hard high pressure lines torque down pretty good on the injectors, so then putting the returns on, it they aren't fully sealed and tightened up then when the high pressure line is installed it could tweak it over just a bit and cause a leak. There isn't much play in the hold down bracket but I like to twist the injectors clockwise however far it will go before installing the return lines and double checking them before putting the cover on. It's just another item to help prevent leaks

Hey anything that helps assure not going back in there is worth it.

Thanks for clarifying.

 

[LB7_01DURAMAX]

Not sure if you figured it out but I had same problem when I put new injectors in and i forgot to torque my returns lines and that is what was leaking. So I had to pull it back apart, first ones I ever did and didn’t even think about it. Learned from that one for sure