So this issue started last summer. We have a linkbelt 330lx with the Isuzu engine that has always ran flawlessly. Last summer it started smoking anytime it idled for more than a few minutes, or anytime it got a heavy load on it. Smoke had a blue tint. Never burns oil so we figured one of the injectors was either going out or stuck open, giving it too much fuel. Couldn’t really take it out of commission until winter so we watched it and it stayed the same. One day in late fall it randomly quit smoking. Still running good. The same day it developed a small leak on the fuel pump. Just a gasket. So while I checked that I double checked oil again and it was full of diesel. Drained it out, and let it settle. Figured we had about 1 gallon of diesel in the oil. Could have only ran like that for an hour or 2. Swapped oil and filters. Ran it for a couple hours and it is still getting a little diesel in the oil, and absolutely no smoke. I’m assuming either the rings are shot or injector stuck open still. Looking for some help on how to figure out what would be causing the fuel in the oil and why it would not smoke all the sudden
pump guy will probably have the good info, but I have seen pumps that put diesel in the oil. The 3406B can do it.
I don't know what model Isuzu is in that machine but if it could be a pump seal leaking fuel into the engine if the pump is bolted directly to the gear case. Could be a leaking connection at the injector, under the valve cover or even a leak in the injector leak-off line under the valve cover. Again, I don't know what model of engine is in there so it may or may not have some of those components.
It has the 6hk1 in it.
If it has a lift/supply pump, check it w air. Get the injectors checked.. If the injectors don’t fix it, pull the pump..
Been a while since I had a 6HK opened up. I do seem to recall they have a leak-off line from the injectors that is attached with banjo bolts. I'd check that pipe out since I think its right there when you pull the valve cover off.