My D4H has developed a bad habit. Hydraulic oil gets into the engine. Not sure how long has been going on but engine 4 inches or so overfilled. Very little external leaks although does go through some trans fluid. Unit runs properly. Thanks for support.
I'm not familiar with that dozer but I suspect that you have a hydraulic pump mounted on the front timing cover of the engine. It sounds to me that the shaft seal on that pump has failed and it is transferring hydraulic oil into the crankcase. Good luck and I hope that this will help. In the meantime post the serial number and someone will be able to help you better.
The unit is a D4H LGP series 111 with 124 HP engine. The serial number may be 96J01931. The pump seal mentioned sounds possible. Will look at front of engine.
your serial # should be 9GJ. 96J is a D 5. You sure it's not transmission oil? Bob
The serial number is 9GJ as Bluox indicated. A additive in Hydraulic fluid indicates source. Might someone have a illustration or repair write-up they could share with me. I have not found hydraulic plumbing or pump on engine unless below crankshaft centerline.
Implement hydraulic pump is located under the floorplate in the operator station. It mounts on the back side of the converter along with the powertrain oil pump. You can identify which pump is which because the powertrain oil pump is a 2-section gear pump, the hydraulic implement pump is a variable piston pump with the pressure/flow compensator valve mounted on it. With that arrangement it seems strange to me how hydraulic oil would find its way into the engine. If oil leaked from the pump into the torque converter housing surely it would be scavenged back into the transmission case.?
That is not a nice job. good luck Bob
Makes me wonder what kind of oil cooler packages are on this set up?
This will sound strange... But I had a Case 821 transferring hydraulic oil into the trans, ok the pump is leaking, right? I started pulling panels and found the real issue. A medium pressure hose had rubbed on the fill tube 'til it put a hole in the tube, then the hose rubbed 'til it got a pinhole. Pinhole fed the tube and never leaked a drop externally. Go figure. There may be a similar issue here from a cooler line, etc. ?
No implement hydraulic cooler DM, so that rules that out.
Nige are the converter housing ran in oil on these machines?
Now there is a thought, Converter housing NOT draining sufficiently, also not venting off where floods the rear main seal, possible?? Thanks for that Nige on the no implement oil cooler. Would not have considered none.
The converter housing is not full of oil, but it will have oil in it that leaks out of the converter during operation and is then scavenged back to the transmission case. That’s why the power train oil pump is 2-section, one supply oil to the transmission & converter, the other to scavenge the oil from the converter housing.
Remember it's hydraulic oil getting in motor oil.
Please read post #8 above. - Both the implement pump and the powertrain oil pump are mounted on, and driven from, the back side of the torque converter housing. If the hydraulic implement pump was leaking through the shaft seal the oil would end up in the torque converter housing, from where the scavenge pump would return it back to the transmission case. In those circumstances the level of the transmission oil would be rising. To quote your OP - "Very little external leaks although does go through some TRANS fluid." Like Bloux asked you earlier - are you SURE it's not transmsission oil..? Because the design of the system makes it very unliikely that it is hydraulic oil. How much is the level of the hydraulic tank falling.? And if the engine oil is black (or at least fairly dark), as it normally is on most diesel engines, what are you using as a test to determine that there is an additive from the hydraulic oil in it..?
I'm wondering if it's not fuel in the crankcase. Again I am not familiar with this machine but from what I've read from Nige. I don't see any way for hydraulic oil to enter the engine or transmission oil for that matter. That leaves coolant and fuel. What engine is in this little dozer?
Powered by a 3304. I could see power train oil getting into the engine if for some reason the converter housing was flooding (excessive internal converter leakage or an under-performing scavenge pump). Under those circumstances it ought to be possible for power train oil to get into the engine via the rear crankshaft seal.
I see your point about the powertrain oil flooding the converter housing. But I would assume that if that were the case there would be other symptoms. like a parasitic load on the engine from the converter slogging through the oil after it floods out. Some days I wish that I could fly around the country and give people a hand in troubleshooting these sort of things. Sometimes information isn't clearly communicated or is omitted for whatever reason. And that bit of information could make all the difference. I hope to see this get solved. It definitely has me interested.
Actually the power train pump is a 3 section pump .The implement pump should have a witness hole between the 2 drive shaft seals, so if seals are leaking hydraulic oil would dump in belly pan. Maybe Dozer could enlighten us with the rest of the story? Bob
Trans fluid goes down to add mark in about 5 hours. I retorqued bolts on rear housing and that seems to dry up that leak. Blade tilt cylinders leak at packing. They might leak a cup of fluid in 5 hours . Not nearly as much as is lost into engine. I know Hyd oil in engine due to additive added to hyd tank on right rear. I added some slick stuff (like old STP Engine additive)to hyd oil on right rear fill tube. The engine oil is slick and trans fluid is not. So I know hyd oil is getting to engine by some means. Yes, I probably overfilled hyd oil but it continues to lose fluid as it goes below add on sight glass. Will remove some covers to get better ideal of hyd circuits. Also, will remove some engine oil and have it tested. Have a box full of sample bottles paid for. Hopefully this fills in most of the blanks from discussion. Dozers are not my strong suite as spent 40 years in auto repair business. Thanks for your efforts. Owen
Trans fluid goes down to add mark in about 5 hours. I retorqued bolts on rear housing and that seems to dry up that leak. Hydraulic fluid will drop beyond sight glass in a hour or so. Blade tilt cylinders leak at packing. They might leak a cup of fluid in 5 hours . Not nearly as much as is lost into engine.
Bob's correct. I looked at it and saw it was more then one section and assumed it was two, one for supply, the other for scavenge - just goes to show that you should never assume. The third section of the pump feeds the steering clutches and brakes. If you have a sample of engine oil analyzed it will test for water, glycol, & fuel among others. All of those should be eliminated as possible causes for a rise in engine oil level.