12 quarts oil out of my LB7... :(

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Changing my oil today before a 2500 mile holiday road trip, and noticed it looked thin coming out of the fumoto valve. Then I completely filled up three 1 gallon containers with the waste oil. Sigh. 110,000 miles, and I have noticed a slightly rougher idle, nothing major though. So I called the dealership and spoke to a service writer about their schedule. He advises no back order or supply issues on injectors, and said 3-4 days or so should do it but their HD techs are a bit busy right now. He said it sounds like injectors but might not be. I'm not sure of the in-house testing they do to ascertain the specific malfunction. If anyone can bring me up to speed so I might know what their terminology is I'd appreciate it. What other things might cause the diesel in the oil if not injectors? Is this a fairly simple diagnosis, or might I expect a run around? Thanks...

[Mark Rinker]

Nice catch. At least you now know of the problem.

There are only two liquids that can dilute the engine oil. One is diesel from bad injector(s), the other is coolant.

If your LOW COOLANT indicator hasn't lit, and the level is good, its probably injector issues. You'll get a light and notice the level in the overflow jug is low with as little as 2 quarts gone.

Did you see any unusual exhaust smoke? I know its harder to notice in the winter. You can also smell the unburned fuel in the exhaust.

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Appreciate the reply! You know, the coolant light did go off and on twice in the last oil change interval which puzzled me, I added a bit (first add in 100,000 miles) and didn't think of it again. Tell me more on this scenario please. Been using the Ultra Low fuel, mainly noticed the funny smell and that general smoke has been reduced compared to earlier observations.

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Furthermore, the coolant light never stayed on and the truck was parked on a slope which led me to discount the warning somewhat. I have had some 'no-starts' which I initially thought had to do with Juice, but have still had more since removing the box. I typically unplug the main harness connectors and then re-plug everything and that usually does it. Head gasket is normally replaced with injector service, no?

[Mark Rinker]

No. Head gasket service is independent from injector service.

They should be able to test your oil and get a good idea of whats diluting it. Maybe one of our GM techs can chime in to tell us how they will likely diagnose the problem...

If its injectors, you're covered. If its a head gasket, and you've been running power adders, be ready to 'pay to play'. No whining. :)

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Understood. I pretty much ran the box on 1, for improved throttle response, the speed correction and EGT features. It's totally a work truck and has never been pushed hard, but has hauled/towed lumber. Tell me, wouldn't water/coolant type dilution make that Sludge mixture, not being compatable with oil? I cracked a block way back when on a 327 and there was no mistaking it.

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Update for those following my situation: After the oil change where I caught the extra 2 qts, etc., I drove on another 2500+ mile road trip, and the oil level again has increased. Just took it into the dealership and they have verified an injector problem (CH codes P009, perform CHS per work sheet return flow excessive both banks). The injectors are now on back order and estimated a week or so out. They have returned the truck to me until then.

Are there any negative consequences in continuing to drive the truck (on a road trip) until parts arrive? Don't want to suffer a break down out in BFE...