Hey guys I have a couple 6.2 L gas f250 super duties that we use and I have got a couple of bad oil sample reports back on them. 1.7 % fuel dilution and 37 ppm lead. The fuel dilution slightly decreases the viscosity which increases wear. What have you guys been seeing, normally fuel dilution isn't a problem on gas engines. Have around 30,000 miles on them, bought new from the dealer. Let me know what you think, thanks for the input!

winkershop

 

I have no input to what may be causing this but I am curious what intervals the oil is being changed at. Is it being done at set mileage or when the oil minder says to change it.

 

Unless there is a very recent change to the oil monitor (like for '15), there is no "monitoring" of the actual oil. It is strictly an odometer reading of 7500 miles that sets off the "needs oil change" message. Found this out on previous service when the kid at the dealer forgot to reset my service interval. Was confirmed for me by the service manager when I called.

 

Good to know. I wonder why they don't shorten that interval up Ford knows these trucks are worked.(Or are meant to be)

 

Reviving an old thread here. I do motor oil analysis with Blackstone on all my vehicles. My last report on my 6.2L 2012 F250 came back with fuel dilution also. I just use the vehicle to tow my fifth wheel, so it sits all winter and doesn't see a lot of mileage. Anyone have any insight on fuel dilution? Could leaky injectors be an issue? @winklershop did you ever get to the bottom of your fuel dilution issues?

 

As stated on the lab report, cold operating will show higher fuel dilution in the oil. Moisture and fuel in the oil evaporates considerably when the engine is at operating temperature and vents out the PCV. Its best to operate the engine for a good 1/2 hour at operating temp and then drain your oil and send it in for analysis to avoid inaccurate readings of fuel and moisture from cold operation or sitting unused.

 

I did the oil change and sampling with the engine hot - I don’t think that’s the issue here. Should have mentioned that in the original post.

 

Was your oil change done right after a long drive towing your camper, or was it more along the lines of the truck sat around a while unused or used for end of the season/beginning of season short trips under 1 hour runtime? Just trying to isolate the actual oil change conditions prior to pointing at an actual engine related issue as the cause.

 

Good question. I live in Montreal - and park the truck outside in the storage yard for the winter months - December through March. I'll head out to the storage yard a few times over the winter to reconnect the battery, run the engine for an hour to warm it up and keep the battery charged. The rest of the year the truck gets weekly use - may be a weekend camping trip or errands for the house and yard, and one or two week long trips with some decent mileage. At the end of the season I'll do an annual oil change in December right before storing it - so that the oil has the minimum of contaminents while sitting over the winter. When I did the oil change last time I had the truck out for an hour running errands - everything was at operating temperature - and when I got home dropped the oil within 10 minutes of stopping. I basically did the same thing for the past two years - didn't have any fuel dilution on those oil changes.

 

From what you described from your use case, I would lean more towards it just being the run cycles prior to the oil change not being enough to evaporate the fuel in the oil. Ultimately, I would use your truck and prior to the next oil change head out for a 2-3hr highway drive keeping RPMs up over 1500 and then change the oil and send it out for analysis.

If your oil sample still comes back with comparable fuel dilution, then yes you have an actual engine problem contributing to it. As your engine ages you will have more blowby in the cylinders contributing to fuel dilution. Nothing wrong with that, just make sure your PCV stays functional, if that plugs up the vapors wont vent from the crankcase.

I have old trucks that make shop to town runs,10-12 mile trips maybe 1 hour total run time. They are mechanically sound but if I pull the oil for analysis it will show considerable fuel dilution just from how I use them. If I take that same truck on a 2-3hr run and then change the oil the fuel dilution will be much less.

 

That sounds pretty logical. I'll try that - next oil change will be late next summer, and report back how that goes. Appreciate your time and input on this!