Diesel seeping into oil sump

Bc8774 · Apr 23, 2014

Hello, I am new to the forum and looking for some advice/answers. Have a john deere 4030, diesel is seeping into the oil sump. Wondering what possible causes that may be. I am thinking about inspecting the injection pump orings/gasket. Any additional info would be great. Thank you.

Bob · Apr 23, 2014

1. Failed fuel lift pump.
2. Leaking shaft seals on injection pump.
3. (If the engine is mis-firing)... Unburned diesel migrating to crankcase.

Dick L · Apr 23, 2014

I never owned a John Deere but on both my dorF 961 and Case 580 had that problem and new cup seals were needed on the drive shaft. Both ran fine.

Dick L · Apr 23, 2014

I forgot to say both of mine were Roosa Master's

I found this on ebay that shows the cup seals installed on a shaft.
Here

JDemaris · Apr 24, 2014

The umbrella seals on the injection pump
driveshaft often wear a groove into the bronze
bushing in the front of the pump. Then diesel
leaks into the crankcase. Also - if the plastic
dampener is falling apart inside the pump - small
pieces are probably restrict flow of fuel out of
the pump and putting pressure on those seals. The
Stanadne/Roosamaster pump has a pressure-regulator
that keeps inside housing pressure at 2-4 PSI.
When it plugs and pressure rises - fuel forces its
way past those umbrella seals. The "housing
pressure regulator" is the fitting where the fuel
exits the pump and has a small spring and ball in
it. New one cost $6.

Bc8774 · May 5, 2014

If it is a failed lift pump, recommend replacing the entire lift pump or just the gasket?

Diesel seeping into oil sump

Bc8774

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Bob

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Dick L

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Dick L

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JDemaris

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Bc8774

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