M35a2 fuel in oil

Hey guys im new here to steel soldiers...i own a 71 m35a2, and my oil level has recently gotten higher and the oil is really thin now and smells like diesel. I know the oil flows somewhere around the injectors. So if anyone has any answers for me it would be greatly appreciated.

Could be the fuel compensator if it is still hooked up. I think that is why the military bypasses them

Also the intake heater if it has one. There have been some threads on this problem, so it should pop up in a search. Good luck!

When it happened to me it was the little rubber o-ring on the fuel cut off shaft.

Check your oil before you crank it every time....that happened to my Cummins in the 816 and when I fired it up it ran away because the fuel/oil mix got sucked into the cylinders and the only way I shut it down was by cutting off the air.

Once you find the source of the leak you will need to change the oil and filters.

How about the o-ring between the injection pump and the gear housing. Means the o-ring that should seal the injection pump. A friend of mine once had this problem.
Wolf

Is the fuel compensator the only way that diesel can get into the oil? Just wondering if that potential problem is completely eliminated when the compensator is bypassed.

I think the compensator leaking is very common, I have had a couple that were bypassed and only one that was operational. When you bypass it there is no fuel running through it anymore so no chance of leaks from it. It is possible it could be a bad seal elsewhere but if you bypass the compensator just to test I think that would be the easiest place to start. You have to move a few lines around but you don't need to mess with the pump.

I agree, the fdc is the easiest first step. No it is not all that can be wrong, but it is a know issue.

Thanks for the info on the FDC guys' im gonna give it a shot in the morning and see if it fixes the contamination.

Thats the only thing that sucks in this situation. Lets say you eliminate the FDC from the fuel syst. Then you change the oil and there is still a leak in to the crank-case. You just wasted 5gal of new oil(sucky-sucky). Does anyone know of a way to avoid that?

gimpyrobb said:

Thats the only thing that sucks in this situation. Lets say you eliminate the FDC from the fuel syst. Then you change the oil and there is still a leak in to the crank-case. You just wasted 5gal of new oil(sucky-sucky). Does anyone know of a way to avoid that?

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For a multi, filter and use the mix as fuel.

gimpyrobb said:

Thats the only thing that sucks in this situation. Lets say you eliminate the FDC from the fuel syst. Then you change the oil and there is still a leak in to the crank-case. You just wasted 5gal of new oil(sucky-sucky). Does anyone know of a way to avoid that?

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Tell me about it! I just changed all the fluids over to Amsoil. Planning on switching the engine oil over into the LDS when I swap that in. That would be some really expensive fuel.

jesusgatos said:

Tell me about it! I just changed all the fluids over to Amsoil. Planning on switching the engine oil over into the LDS when I swap that in. That would be some really expensive fuel.

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Holy smokes! Is that $200 worth of oil I see? I'm cheep. I'll buy SuperTech, Delo, or any house brand that at least meets Cummins and Mack specs. The last oil I bought was Loves brand 15w40 at a truck stop in bama. Hey, it was on sale!

That's just the engine. These deuces hold a LOT of oil. But I only want to do this once.

I know they hold a lot of oil. A deuce I just picked up was overfilled from DRMO (by about 2-3 gallons I'd estimate), so I did a parking lot oil change at a Loves Travel Center. Dad asked me what oil to get. I said get one case of 15w40. Whatever is the cheapest. The multi was fine for the rest of the trip, no more puking out of the breather.

The sight of Amsoil gives me sticker shock. With bypass filtration, I guess it makes sense though?

To the OP: Bypass the FDC. Disconnect the flame heater. Replace O-rings under HH. That is what I would do in that order, using cheap oil for the oil changes in between until you stop getting fuel in the oil.

You could just bypass the FDC and hope for the best, or you could test it. The FDC unbolts from the injection pump with 4 screws. Remove the screws, and lift the FDC out of the IP. With all of the fuel lines connected, turn on the accessory switch so that the in tank fuel pump starts pumping. Then sit back and watch the rod and smoke lever that comes out of the bottom of the FDC. If it starts dripping, it is a problem. If it doesn't, it isn't. It is ok for the rod to be wet. You have to use your judgment. It takes a lot of drips to dilute 6 gallons of oil.

The reason the FDC can so often be a problem is the steel shaft that comes off of the FDC piston has no seal, save for the very close fit between the shaft and the casting. If the fuel is dirty, and wears the shaft and hole, it will start to drip fuel. The only way I can think of to fix the problem is to bore out the hole, press in a bushing... and probably replace the shaft.... That or burn nothing but motor oil .

-Chuck

bassetdeuce said:

I know they hold a lot of oil. A deuce I just picked up was overfilled from DRMO (by about 2-3 gallons I'd estimate), so I did a parking lot oil change at a Loves Travel Center. Dad asked me what oil to get. I said get one case of 15w40. Whatever is the cheapest. The multi was fine for the rest of the trip, no more puking out of the breather.

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One thing to note: the deuce will only read FULL on the dipstick at 60 seconds after shutting down the engine... After 6 or more hours, when all the oil has returned to the oil pan, it is supposed to read 1-1/4 inches above the FULL mark.

-Chuck

stumps said:

One thing to note: the deuce will only read FULL on the dipstick at 60 seconds after shutting down the engine... After 6 or more hours, when all the oil has returned to the oil pan, it is supposed to read 1-1/4 inches above the FULL mark.

-Chuck

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Thanks Chuck, but I know this. This aint my first rodeo. My dipstick was reading about 5 inches above full after sitting for a minute beyond shutdown. Needless to say, whoever checked the oil before me was a dumbazz.

bassetdeuce said:

Thanks Chuck, but I know this. This aint my first rodeo. My dipstick was reading about 5 inches above full after sitting for a minute beyond shutdown. Needless to say, whoever checked the oil before me was a dumbazz.

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Cool!

I would bet that the PMCS depot has a huge tank full of 15W40 oil with an electric pump on it. Someone probably wasn't paying attention to the meter on the pump.

-Chuck