I have a 95' ser 60 det 11.1 365 h.p. Let's back up 20 months ago... I had an injector to start leaking. bad. I took in to local freightliner dealer. they put in all 6 injectors & overhead, e.t.c. at that time the truck had 1.1 mil miles on engine with no previous major work done. after getting truck from dealer, it had more power & better m.p.g than ever before. it never had that much power in the last 11 years I have been driving the truck & I bought truck with 400,000 miles on it. the one thing I also noticed was a noticeable increase in black smoke out the stack too, though I could go to places where previously I had to drop 1-2 gears on certain hill's to not dropping any. now..been great until.. fast foward approx 2 week's ago. I found coolant in my oil. dropped truck off at local shop who specialize's in detroit's. I figured what ever the cause, now with over 1.3 mil miles, I decided inframe reguardless. I went to look at truck couple day's ago. engine all apart. man say's the valve guides were so worn that it caused the valve's to hit the piston sleeve, & I think the sleeve seal. the cause of valve defecting was high mileage but moslty due to the ulsd, is what mechanic said. I saw the scratches & gouges on 2 of the liners. he told me that if it were not for the valve's causing the coolant leak, he thought I would likely have went another 500,000 without a problem , with the exception of more ring wear. he told me to keep doing what ever I have been doing with truck, cause he has not seen a engine with over 1.3 mil , have so many good internal part's. inspected gear train, siad looked great, cam looked great( I saw cam it looked like new) the liners or piston sleeves he said looked great on the out side. no pitting at all. except for the damage done by valve's , he said never seen sleeve's look that good. one thing he mentioned was the injectors that were installed 20 months prior by freightliner, was for a 12.7 detroit. I said well that probably explains the increase in power. he suggested we use the same cam, same injectors. all other part's will be replaced with new, main's inserts', cam bearing's, sleeves, e.t.c . what ever is called for in a inframe. does any one have any insight, recommendations,commet's on cause of problem with the sleeves getting battered other than the diagnosis here, or with the rebuild? thank you.

 

Sounds like the cylinder liners were damaged by the 'coolant in my oil' problem.

Check counterbore ledges for damage.

 

The shop mgr said something about counterbore