willysmjeeps.com

I think there may be a problem with my 1953 m38a1 , there seems to be a strong smell of gas on the dip stick . the oil was changed last fall ,so I fired it up for a short drive today and noticed the oil pressure switch was showing lower pressure than normal. the jeep work fine but I,am concerned about the smell of gas in the engine.The oil did look very discoloured,for new quaker state oil. Any idea ,s what to look for. thanks Lake

It is very possible that the diaphragm on the fuel pump side is cracked and leaking fuel into the oil pan causing it to thin the oil and have gas smell, this has happened on occasion.would need to replace or rebuild the pump.

Your fuel pump is needing a new diaphragm. DO NOT run your engine until you change the oil and fix the pump. The gas will wash the engine clean and wipe it out.
John

Very good advice from John:

The gas will wash the engine clean and wipe it out.
John

By "wipe out" john means destroy the parts of your engine that use engine oil to protect them from friction.

O.k thanks, guys I will not run my jeep until the oil has been changed and the fuel pump has been checked for damage .Would there be a diagram of the fuel pump any where before I challenge this project. Thanks Lake

Go to Downloads, TM9 1828A.

Does this apply to the M38's as well? I was told a few years ago that with the fording system on creating positive pressure that was how the gas smell got into the oil.
However, it sounds like that may not be the case after all. I'm concerned because I've driven it in a couple parades and around town lately and while I haven't noticed any engine trouble, aside from running rich, I don't want to cause any long-term damage.

Any engine with a mechanical engine mounted fuel pump could have this issue if there is an odor of gasoline in the engine oil.

Same happened with my A1 recently; I suspected a cracked diaphragm in it before putting it in the shed last December to get all the work done on it. The oil had a slight darkening- more of a blackish/gray color- and not the normal oil color after some miles have been put on after an oil change. No gas smell, just the strange color.

Last week, I finally- after a long wet,cold winter- got the jeep out and drove it. All seemed in good shape, but it was quickly obvious that the diaphragm was leaking: gas smell in the new oil, etc. By quickly obvious, I mean that I drove it a few times around the block and that was enough to see the problem. I had already bought the rebuild kit from MM and will now put it in. But I wasted $10 in oil by not changing out the diaphragm prior to the oil change. And the oil this time was the exact color as it was before.

Anyone know why it is you can't buy the rebuild kit for the vacuum portion of the pump? Is it because the diaphragm is no longer made?

Also, I was looking at the TM download; is our A1 pump the BK version?