LB7: Massive diesel fuel leak into crank case

crazyhickboy03

New member
Apr 13, 2012
6
0
1
Midwest
Alright guys I got one that's kickin me here, its an 01 chevy duramax customer complained that it need injectors when he showed up it had huge amounts of diesel fuel in the oil. Drained the oil and put a reman set of injectors it in. Got it started and took it for about a 25 miles test drive, got almost back here and pulled over looking at the balance rates and the truck was missing horribly bad. Made it back and looked down and had little no oil pressure. Shut it off got in inside and fuel was running out of the breather tube. Started it back up and the oil fill cap had a ton of pressure on it. Took a light and looked down in there and could see diesel fuel running into the oil fill. My thoughts were CP3. I put a tech II on it and tried maxing the pump out and it would only make 13,xxx when I commanded it to make 23,000. Put a new pump on drove it again everything seemed good. No more pressure, no more fuel in the oil fill either. Now heres the kicker; I get a call this morning he drove it an hour home and he got home and its doing the same thing, he said the oil is completely over filled and fuel is coming out of the breather tube again onto the ground.

What the heck am I missing?
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
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Texas!!!
Could be a blockage on the return side causing the seal on the CP3 to blow out.
 

crazyhickboy03

New member
Apr 13, 2012
6
0
1
Midwest
Hi guys, just wanted to give a follow up, ended up having too bad high pressure lines even though they were cranked to spec they still leaked. Put it back together and works perfect.
 

Randy1156

New member
May 5, 2013
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Wow second day newbie here. and sounds just like some of the crap I'm getting into with this lb7 . going to build a tool like I think was Travis's and check for leaky return rails today.
with the fresh re-man cheap injectors who knows as i was told yesterday this truck is sucking my Buddy Dry with oil changes parts and hauling it around and crappie GM techs around here that want $80 an hour to test then don't tell ya crap!