I found a 85 F250 6.9 diesel 4x4 for sale near me for cheap and it is rust free. The problem is he says he thinks the motor is about to let go. He says it started having a loud knock in it and he pulled an injector and said it was covered in oil. He then is specualting that it has a hole in the piston. He said it has 217K on it. What do you guys think? Could I spend 2000.00 to have the motor rebuilt or do you think it something else. I am a diesel newbie here, but I have thought of possibly replacing the motor and tranny with gas motor since everything else is perfect, would rather keep diesel but if the 6.9 is going to cost much more than 2k to rebuild then I might. Any thoughts

Larry

 

Start the motor and pull oil fill cap off. If it has a hole in a piston you won't miss that. That knock could be just a fuel knock. A diesel motor can have a fuel knock that is louder then an actual lower end knock. It could be over fueling and that is what you are see on the nozzle.

 

Depending on your local shop rates, you may be able to overhaul it for 2000 if you do most of the work yourself.

I had about 4000 dollars in parts and machine shop work in mine when I rebuilt it, but I did have a lot of extras done since I built it to run high boost.

 

It cost me 3500 to have my 7.3 rebuilt in Arkansas. It had a hole in piston #1 there was no knock and it still started and ran OK, BUT It smoked White a LOT.