I bought a 1985 International bus 6.9 non turbo a couple of years ago. It has always been using oil at the rate of about 3 quarts every 100 miles. It is not leaking the oil, it is burning it. The engine has 148000 miles on it. It starts easy even in cold weather and runs great with no miss or loss of power.

I replaced the cdr valve with a used one, since the diaphram was bad in the origional one, still same problem. I just ordered a new cdr to make sure I don't have a defective one, will be installing it this weekend.

I also did a compression test last weekend with the following results: 1)410, 2)385, 3)385, 4)440, 5)465, 6)440, 7)440, 8)450. I did have the left head replaced last year due to a crack. the replacement was rebuilt. This is probably why the compression is higher on that side. The oil burning remained the same after changing this head.

Any ideas what is causing this? Valve seals on one head? Would a bad oil ring cause this problem and not show up on the compression test?

Any help would be appreciated.

 

Check all your seals, after a few years they dry up n crack.replace or look at yourfront main, rear main, and oil pan gasket to have all of the oil seals replaced

 

Do you think oil is blowing out of the seals as it goes down the road? It does not drip any oil when it idles or sits in my driveway.

 

I dont know. I read that this is common for these, also common for going through oil.. Do a history check on the engine its a interesting read up.http://www.dieselpowermag.com/tech/f...e/viewall.html



heres a good read on a common problem,CDR Valve - Diesel Forum - TheDieselStop.com,




I also read about using a 7.3l oil fliter on the 6.9's


good luck.

 

Pretty sure it is an oil ring problem. Trying to figure out if it's worth re-ringing it.

Thanks