fuel in oil

I have a 1993 Series 60 12.7 with about 1.5 million miles. I've been running it 13 years with very few engine problems. I'm probably running the original injectors. I've put about 900,000 miles on them and I've never changed them.

This happened suddenly-today-after 13 years and 900,000 miles. Maybe that's a clue.

Any ideas where to start looking and how to go about it?

 

Thanks rebel.

 

The problem was bad O-rings... cooked hard... probably almost two million miles on them.

Engine's back to normal.

Thanks to everyone for the advice.

 

I bought the truck in 2000 from a Freightliner dealer. It had been a Penske fleet truck. The mileage was about 700,000. Since then, I've put about 1,200,000 miles on it. I've never had the head off, the pan, or the front cover.

I don't know what Penske did to the truck. I suspect they sold it at the point they figured it might be more of a maintenance liability than an asset. That's why I think the injectors are probably the originals, but I don't know for sure. They have at least 1.2 million that I've put on them.

The engine uses a lot of motor oil, but no more than it did when I bought it in 2000. It leaks motor oil and it burns motor oil, about a gallon every 2,500 or 3,000 miles. I'm told that's a lot, but I'm not about to tear into the motor. It's too dependable.

I get about 7 mpg when I keep my foot out of it, and about 6 when I've been pushing it.

I've been using Delvac that I buy at the Walmarts.

It's an FLD 120 and I run most of the 48.

The only things I've replaced are stuff like turbo, alternator, radiator, CAC...