fuel in crankcase

[racingcarpenter]

I have an 02 with 136000 miles. only mods are superchips programer. Three weeks ago came back from Atl my mileaged drop by 2 mpg and oil pressure dropped to 20-25 psi. Had to use it at work the next week, it filled the case with diesel and poured out on customers new driveway. Truck ran rough that day but since idles and runs fine but still leaking diesel in to case. Not sure if its an injector of pump. Any help to figure it out would be greatly appreicated.

[DickWells]

On your LB7, the fuel return lines run inside the valve covers. Your excess fuel is more than likely coming from a leaky line. That's about all I know about it, so, someone else will jump in here and give you better info. You'll no doubt get some better poop from the experts, by Monday.
Good luck.

[racingcarpenter]

Thanks for the info. I'll be starting in that area on thanksgiving. It will get me away from my family for a little while. haha

[Kennedy]

Unfortunately, most often a crankcase full of fuel is from leaking (cracked) injectors. Fortunately, the crankcase filling does not seem to be an issue with the later replacements. I always recommend replacing all 8 High psi lines as well due to corrosion issues external to the fuel supply, but in a location that will transfer into the injector inlet when removed.

[DickWells]

Well, I just went through my Duramax 6600 R&R books, (By Jim Bigley), just to refresh my memory, and didn't satisfy myself very well. I was looking for confirmation of what I said in my first post. But, I see the fuel/injector lines, but don't see any - separate - return lines, so, my previous statement could be off. Nevertheless, these lines do run under the valve covers, and I know from previous threads on the DP that a "fuel in the crankcase" issue is probably from that source. So, just have patience, and the "real" DM guys will be on here, helping you out.
BTW, those R&R books from Jim are worth more than you'll pay for them. I have a complete set, back home, for my old 6.5 Suburban, and keep Vol I and II of the 6600's in our trailer, wherever we go.
Good luck, again.
Dick:)

[More Power]

I suspect some of the LB7 oil dilution problems were due to loose or leaking injector return lines, beneath the valve covers. The return lines use banjo fittings and brass washers on the injectors. I agree with JK that most leaks were likely due to cracked injector bodies. At the time, we were told that the injectors susceptible to cracking was a fairly short production run, and that Bosch got on top of the problem before large numbers of them had been produced.

Jim