671 Detroit

Hi guys I have an old Terex loader with the 671 Detroit and it’s been a great runner we had the pan off not long ago and everything looked wonderful in there there was no metal in there anywhere and things were just looking great anyhow recently this thing out of nowhere has gotten wild crazy crank case pressure and it’s blowing oil out the vent on the side of the block like crazy and I’m at a loss I’m not sure where it’s at does anybody have any ideas I’m leaning towards some thing with the blower maybe because it’s Massive volume of air

Welcome to the Diesel Page. This site is mostly for 6.2, 6.5, and Duramax diesel motors. I will try to help you with the problem if I can. First do you have a 6V71 or a 6I71 (inline) also does the motor seem to be making motor oil. If you are making oil you most likely have a broken injector line under the valve cover. Is the motor making any hammer noises when running? Those 2stroke motors are easy to work on and you can look at the piston rings and pistons by removing the air boxes on the side of the block. You may need to remove the exhaust manifold to remove the air boxes. It is very unlikely that the blower is the cause because you would need to have a blown piston to put blower pressure into the crank case. I havn't worked on a DD 2stroke since the 1970s so this is a memoty test for me. Let me know what you find.

Good luck
John