Diesel Fuel in Engine Oil

Tom in Norridgewock · Aug 2, 2009

About two quarts of diesel fuel has leaked into the the engine oil in the crankcase of my MF135 w/ Perkins diesel. I replaced the lift pump and then noticed that there was fuel leaking from the injector pump timing cover. [I haven't run the engine since replacing the lift pump.] I removed the timing cover and about a pint of fuel oil poured out. What now??

DavidP,South Wales · Aug 2, 2009

Hello Tom,
The diaphragm in the lift pump would have been the most likely cause of fuel getting into the sump. You have changed the lift pump so we can exclude that. From your description is it only the access plate to the pump gear that you have removed? You should certainly not have had any fuel from here. Your problem is almost certainly the seal in the front of the main pump allowing fuel into the sump (pan). What concerns me more is the fact that fuel flowed from this cover. There should be free passage for oil used in lubricating the timing gears to run to the sump. Clearly it is not doing so.
I would suggest that perhaps there is rag or paper towel causing a blockage unless of course it is to do with the sump gaskets.
Please confirm that you had fuel from the pump gear access plate.
Regards

DavidP, South Wales

Billy Shafer · Aug 2, 2009

To me the timing cover on this pump is on the side and you will get fuel from there. If you mean the cover that has the oil fill spout then no you should not have fuel there. I just had the pump rebuilt for a M135 Perkins. If the front shaft seal is leaking. You will be dumping fuel into the oil.

Tom in Norridgewock · Aug 2, 2009

I have diesel fuel in the engine oil. I had diesel fuel leaking from the timing gear access that is on the outside (left looking forward) of the injection pump. This diesel fuel was clean; no engine oil in it.

Tom in Norridgewock · Aug 2, 2009

Yes the area of the timing gear was full of diesel fuel; it was clean and clear. Not mixed with engine oil.

DavidP,South Wales · Aug 2, 2009

Hello Tom,
I'm still a little confused here, your further replies appear to give two possibilities.
If you removed the oval plate on the side of the fuel pump you would have clean fuel coming out. The low pressure in the pump would ensure that the fuel found its way into the oil and not the other way round.
Have you removed the access plate which incorporates the oil filler (on earlier models)that is on the front side of the main engine timing cover? If so, did you have fuel out from here?
DavidP

TomTex · Aug 2, 2009

You say you replaced the lift pump, but have not run the tractor since. Why not run the tractor and re-check the oil. Your problem may be fixed already. Tom

TomManning · Aug 4, 2009

My MF35 failed and fuel dumped into oil sump. The main distributor pump shaft is broken. I do not know if there are other issues. I have yet to get the gear cover off.
Hope yours is just a seal problem.

Diesel Fuel in Engine Oil

Tom in Norridgewock

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Billy Shafer

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Tom in Norridgewock

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Tom in Norridgewock

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TomTex

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