I have a 1996 Detroit Deisel Series 60 engine. Its the 11.1 liter. The engine dipstick is spotty and appeared to have something other than oil in it. Now, we've had a problem with this engine for sometime with this problem. Going back about a year ago, we changed the fuel injectors thinking that was the problem. Well.. after that, the engine still appeared to "make its own oil". We never had to add any oil to it and we knew that it was the same way before we ever did the fuel injectors. Now, I'm thinking either the job wasn't done correctly or there is another reason for it. To counteract the fact that fuel is in the oil, we've been doing oil changes every 3000 thousand miles instead of 12000. That works a little, but not really a fix. Two weeks ago, the bus was out on tour and it kept overheating. So, sure as heck, we changed the oil and it wasn't over heating anymore. Im sure after a good while, it will start to over heat again until we either change the oil out again, or fix the problem. Any help in toubleshooting what may be causing this would be greatly appreciated. Thanks so much!

 

you need to perform a static pressure test with dyed fuel in the system to locate the leak... this leak could come up from the injector o-rings or body, or down through the needle valve to the combustion chamber. the cylinder head could also be cracked (most unlikely)

if your crankcase "fueling" makes the dipstick read an inch or more overfull, you must check for bottom-end bearing damage

... this "lack of repair" is destroying the engine, that's why it's overheating

... isn't there a ddc/freightliner dealer nearby?