Diesel in the oil

[3dubs]

Ok now I am enjoying the a/c even though it is a cool 96 degrees outside.

I had a minor mechanical problem the other day with some knocking under the hood and a smoke screen that would make James Bond look lame. When I drained the oil it was liquid. It smelled like diesel too.

So the question is how does diesel get in the oil? I thought it may have gone in when the engine blew but there was way too much diesel in the pan. I think I was told how but would like to know what other people think of.

 

[91W350]

The mechanical lift pump on the right front corner of the block would be my guess.

 

[Hasbeen]

I would check the pilot shaft bushing in the front of the injection pump.
The Stanadyne pump uses a brass bushing that presses / epoxies into the aluminum housing as an "expendable" item.
The drive shaft has two cup shaped ,umbrella seals mounted back to back(rubber) that will deteriorate and / or cut a groove in the bushing.
It`s extremely common and not a very expensive repair.

I have friends in Houston with a fuel shop that I can recommend.

Have you torn it down yet? A blown injector tip will hammer like nobody`s business (like a rod down) and smoke like crazy, but the engine still survive
(unless your luck runs like mine).

Good luck !

Hasbeen

 

[3dubs]

Hasbeen do you have some listening device planted here? I am about to yank it out right now.

 

[HoJoPo]

The mechanical lift pump on the right front corner of the block would be my guess.

I've had the same problem with similar mechanical fuel pumps on gas engines, I agree that you should look at the mechanical fuel pump too.

The diaphragm in the pump is exposed to the crankcase, and when it rusts out it leaks fuel into the oil.

 

[Hasbeen]

Hasbeen do you have some listening device planted here? I am about to yank it out right now.

Good luck! pm if you need a good fuel guy down there.

Hasbeen

 

[Chief_919]

The mechanical lift pump on the right front corner of the block would be my guess.

I will second this. I have seen it many times.

One reason why I like to swap in an electric pump.

 

[3dubs]

I will check the fuel pump first because it is easy. I have a hmmwv engine to put in but want to make sure I don't blow that one. I drive my truck almost every day so I need it to run.