B8200 (D950) diesel in oil (making oil)

[JulBud Ranch]

I'm trying to troubleshoot a B8200 (D950 Engine) that is getting diesel in the oil pan. This was noticed after I saw oil dripping out of the valve cover vent tube. I've taken out the both the fuel pump and injector pump and everything "appears" fine. I already had the injectors inspected and rebuilt by a local diesel injector shop however the problem continues after about 10-15 hours of use. How do I determine if its a fuel pump, Injector pump, or if issue or could it be the valves, pistons, rings?

 

[Russell King]

First determine if the oil smells like diesel fuel or set it in a glass bottle to see if it separates.

My tractor was leaking hydraulic fluid into the crankcase through a bad seal on the shaft of the hydraulic pump.

There are some tractors that do have a fuel pump that does leak diesel into the crankcase through a damaged diaphragm but someone smarter than me will have to tell you if that is possible on your tractor model.

 

[Mark_BX25D]

I would think if your rings are that shot, you would not have enough compression for the engine to start. Same on the valves.

Like Mr. King said, a diaphragm type lift pump on the side of the block is certainly capable of dumping diesel in your pan. Good thing is, that is not a difficult or expensive fix. Easy enough to find, too. Just follow your fuel lines back from the injection pump.

 

[GeoHorn]

Not a tractor..... (but a ‘78 F150)... that TWICE in two years had a mechanical, cam-driven fuel pump which dumped fuel into the crankcase. The internal diaphragm disintegrated and caused the issue.
My Kubota does not have a lift pump but if yours does.....

 

[Dave_eng]

The lift pump is on the side of the injection pump..

There is a replacement diaphragm for $36

Dave

 

[JulBud Ranch]

First determine if the oil smells like diesel fuel or set it in a glass bottle to see if it separates.

My tractor was leaking hydraulic fluid into the crankcase through a bad seal on the shaft of the hydraulic pump.

There are some tractors that do have a fuel pump that does leak diesel into the crankcase through a damaged diaphragm but someone smarter than me will have to tell you if that is possible on your tractor model.

You may be on to something, I drained the oil and it's thin but not appearing to separate. I checked the hydraulic fluid is below the dipstick level after running about 6 hours. How did you find the hydraulic pump leak?

Also I pulled the fuel pump again and checked the diaphragm and it looks good however I will change the diaphragm anyway.

 

[Russell King]

I did not really find the leak but just the crankcase oil level was increasing and that seal was the only possible leak spot. So process of elimination method really.

I did not try to run the tractor without the pump to eliminate the pump, I had nothing to cover the opening in crankcase. I replaced the seal and problem with the oil level problem stopped.

If your tractor is older and you are not positive the hydraulic pump is original you may want to order all possible variations on the pump seal. Mine had three possible part numbers and the serial number of the tractor did not get the correct seal so I had to order the others to get the correct part in a shorter time. If you don’t mind the time to order one by ones.

I guess in your case you have two sources of possible sources so you may be able to mix some diesel in engine oil in a glass jar to see if it separates in a day or so.

Or just replace both parts? And never know which one was bad.

Depends on time or money to solve the problem

 

[Mark_BX25D]

There is a replacement diaphragm for $36

Wow. And it probably cost 36 cents to make it!