Burning off fuel dilution?

[Spetz]

Hi everyone,

I have a fuel dilution issue in my 2003 Mitsubishi.
UOA here:
https://bobistheoilguy.com/forums/u...-diamante-shu-5w40-6817m-oci#Post4900608

I was under the impression fuel evaporates quite easily but I am unsure now with my UOA.

Would I be able to get rid of fuel dilution or should I just shorten my OCI?

What could be causing the fuel dilution and how would I test this?

 

[RayCJ]

When you collected that oil sample, was the engine fully warmed-up and did you grab the "center portion" of the oil as it drained out?

Somewhere in the Blackstone Oil Lab website (link provided) there are instructions on how to collect the sample and they also describe what can happen if the sample is not properly harvested. High fuel dilution readings is high on the list. Drive the car, get the oil warm fully up to temperature, park it for 5 minutes, let the oil drain for a few moments, then grab the sample into a clean container.

https://www.blackstone-labs.com/


Ray

 

[Ducked]

If you replaced the head fairly recently that should eliminate carbon build up from the list of suspects.

OOPS! Wrong thread. (sodding touch pad)

 

[Spetz]

The oil was harvested by putting a tube and syringe down the dipstick area.

I lined the tube next to the dipstick and added about 2 extra inches below the oil level line so I hope it should be ok.

The engine oil was after a relatively short drive, maybe 10-15 mins and about 4 miles

 

[BigShug681]

I'd actually like some info as well on this, my last sample showed having 3.8% dilution at around 6k miles but was on track as far as viscosity for an equally close mileage sample, I want to say there was a difference of about 1k miles between samples, the current being 1k miles farther with a similar Viscosity Index of around 12.2. The sample I received which had 4.8% dilution at around 8k miles showed a far lower viscosity index of around 10.2, which was far lower than even samples taken at 15k miles, and that was when a faulty injectors was believed to be the culprit. This last sample with 3.4% was only driven 10 miles before sampling through the dipstick tube, and was just under being up to temp, I suspect this could be my issue because again the viscosity tells a different story as to what the fuel dilution had indicated.

 

[RayCJ]

The Blackstone collection sample kit has a pamphlet which I just reviewed. They recommend driving the car at highway speeds for 20 minutes. It says that short runs will introduce fuel and moisture into the sample. I don't think that info is mentioned on their web site but, I knew I read it somewhere from them. I happen to have an awaiting collection bottle from them and this is mentioned in the first step of the instructions.

Personally, I would either re-test using properly warmed-up oil or, just wait till next time. The rest of your UOA looked OK.

Ray

 

[Schmoe]

Honda 1.5T is having similar problems as well.