Fuel in Engine Oil

away572 · #1 09-01-17, 08:49 AM

I wondered the same thing about an oil dilution system, if the airplane has one I've never located it (I've had it for about a year and a half). Where would it be located? Could it have had one and it have been partially removed? The reason I ask is because the aircraft was refurbished.

hharney · #2 09-01-17, 11:00 AM

There's a rocker switch for the OIL DILUTION SYSTEM. On my C model it is just to the left of the beacon/nav switch. I never had the system but the panel is labeled for oil dilution. There is a little info in the POH but have never found anything else in the SM. Maybe one of the fuel schematics might call out the system.

Flyer770 · #3 09-01-17, 02:03 PM

Preheating is preferred for cold weather over oil dilution so many planes have had the system removed. At the oil pump there's an inlet for the fuel, tracing backwards there's a solenoid valve which is energized and allows fuel to flow to the oil system. The solenoid gets its fuel at the strainer for early Skymasters. There's not much more detail in the Cessna maintenance manual and I don't have my engine MM with me at the moment.

skymstr02 · #4 10-01-17, 09:12 AM

Another possibility is the engine driven fuel pump seal is leaking allowing fuel to enter the engine from there. I've seen that happen before.
When's the last time that the fuel pump was overhauled?
Was your fuel consumption higher than normal, this wont show up on the fuel flow gauge, but the tanks would've taken more gas to fill up.

Drain all of the oil and replenish, fly local for 1/2 to one hour and check your dipstick again for the smell and the viscosity.

Dave