D41 e seem the oil level gets higher after using. Think its fuel gettin in oil. Where do u think to start . Ran injector cleaner for a shot in the dark ,but im not counting on this to fix my problem. The dozer seems to run fine and only when i start up it blows little black smoke for few seconds. 5500 hrs
Crook injector nozzles the most likely cause. They can be replaced without buying new injectors, thepumpguy can confirm. He's the guru on these matters.