Fuel in the oil- why?

[BigRing66]

I drive a 2004 6.0L Powerstroke with 70K highway miles. A recent oil analysis indicated I have 3% fuel present in the oil. The previous analysis (10K ago) did not show any fuel present, now all of sudden it's there. I'm going to pull a follow-up sample to confirm or deny. I have not had any mechanical work performed on the engine recently, only filter changes (air, fuel, oil). For what it's worth...I run Shell Rotella T 5W-40 Synthetic. What can cause fuel to be getting into the oil?

[ianstew]

leaky injector could do it, worn rings, etc

[Evil Eye]

I agree. Might need to change to a shorter oil change interval.

[Snake]

Any extended idling during this time?

--Snake

[roadrunner]

over the summer i had the same issue, ended up being injector o-rings.
mine was fixed under warrenty so i can't relay any cost or time involved, all i know is what service manager relayed to me; oil drained out of engine and pressurized injectors, check for fuel at drain plug.
hope this helps

[mbahr22250]

My oil analysis has always shown fuel in the oil since day one. It's never been 3%, usually less than 0.5%.

[wildfingas]

You will see some fuel. Generaly less than 2% on average. I have had one sample come back to me at 3% and it was "cautionary". That sample had 8500 miles on the oil. The next sample came back at 1% @ 6k and the last sample was less than .5% @ 5k.

Through Blackstone labs the average fuel dilution is less than 2%. I would wait and see what the next sample comes back at and remember your samples are going to come back with higher number and lower viscosity the higher the mileage is on the oil.

I would not be overly concerned just yet but keep an eye on it.

But as they have stated. Bad injector o-rings or extended idling would cause this. Extended idling is a pretty long time though. I run mine for 10-15 minutes and I see normal fuel dilution in the oil.