I own a 2000 Peterbilt dump truck with a Cat 3126B engine. This truck was overhauled about 100,000 miles ago. I've owned the truck about 8 months now and my problem is I have to add a gallon of oil about every 1200-1500 miles. The truck does not smoke, the turbo or exhaust system is dry and not leaking. I have no visible oil leaks but I do have some blowby going on but not excessive. The truck runs good and strong and this problem has not gotten worse over time. I have the truck serviced every 8000-10000 miles. Anybody got any suggestions?

 

oil could be leaking into your fuel system... have you looked in the tanks for dark fuel?

 

If this is the problem what would the remedy be? Injector O rings?

 

an injector could be leaking internally as well.... but replacing o-rings on all injectors is the first step

 

How could oil be leaking into the fuel system? The fuel injector pump produces much more pressure then the oil pump. If an injector leaks, it'll fill the oil crankcase with diesel fuel.

I've seen the mercedes engine use a gallon of oil a day :shock:

 

quote="Blind Driver"]How could oil be leaking into the fuel system? The fuel injector pump produces much more pressure then the oil pump.

If an injector leaks, it'll fill the oil crankcase with diesel fuel.

I've seen the mercedes engine use a gallon of oil a day :shock:[/quote]


the 3126b, as well as many other diesel engines, use a hydraulically actuated fuel injection system (HEUI). it takes engine lube oil from the base and pressurizes it between 700 and 3,500psi to drive the injector plungers down. the high pressure oil can sometimes leak past an injector o-ring to the low pressure fuel supply system (the two systems are separated by an o-ring(s) at the injector body).