Diesel in oil?

sierradmax · Aug 20, 2012

Under routine maintenece on my 763, I noticed the oil level on the dipstick was quite high. In addition, the oil appeared to be very thin. It's either antifreeze or fuel.

I drained the engine and placed in a clear jug. I didn't see any seperation which makes me believe its fuel. Hwoever, is there a definite way to tell? The machine still runs fine but I'm scared to run it any longer as the oil thins out even more. Besides fuel leaking into the cylinder or bad rings, where else can fuel leak into the motor?

wcampbell47 · Aug 20, 2012

Check the fuel injector pump seal. Neighbor had to rebuild his JD with this issue. Mechanic told him the injector pump seal failed allowing fuel into the crankcase.

coveredbridge · Aug 20, 2012

This happened to me several years ago with my JD 820. The mechanical fuel pump diaphragm ruptured, allowing fuel to enter the crankcase. Replaced the fuel pump and problem was solved. I would definitely check this out before you get involved with the injector pump.

SSdoxie · Aug 20, 2012

The diaphragm/lift pump would be first palce to check for fuel in oil. If is was anti-freeze it should settle out in your sample jar plus the wohuls be other indications such as loss of coolant, constant bubbles in over flow bottle, and probably some smoke due to blown head gasket or cracked head.

sierradmax · Aug 21, 2012

I called my local bobcat dealer and they mentioned to replace the pump first. They gave me a part number, which I referenced. Is this the diaphram/lift pump?
BOBCAT, 753 SERIES, 753 SN 5162, Fuel-System, Sub-Component, FUEL PUMP, 6655216 at Wengers Of Myerstown

SSdoxie · Aug 21, 2012

sierradmax said:
I called my local bobcat dealer and they mentioned to replace the pump first. They gave me a part number, which I referenced. Is this the diaphram/lift pump?
BOBCAT, 753 SERIES, 753 SN 5162, Fuel-System, Sub-Component, FUEL PUMP, 6655216 at Wengers Of Myerstown

That is it.