Loose spark plug = fuel dilution?

[Danh]

I have a 2015 Honda with the 2.4 liter direct-injection engine. Since new, I have noticed a gasoline smell in the engine oil when doing an oil check. Initially, I accepted this as a characteristic of DI engines and/or a result of short-tripping. But as the smell persisted after a 1,000 mile interstate trip I brought it in to the dealer.

You can all guess this didn't have a very productive outcome as dealers seem to lack any tools to evaluate oil contamination. But they did identify a single spark plug that was about 3/4 turn loose. While this didn't trigger a CEL or create driveability issues, could this result in incomplete ignition and fuel contamination?

I realIze it doesn't take much fuel dilution to create a noticeable smell, but hey, this is BITOG so why not worry? Time will tell, I suppose, and I can always draw a used oil analysis sample but until then I'd appreciate any thoughts or shared experience. Thanks.

 

[Chris142]

No correlation

 

[CT8]

Change the oil if you are worried about the gas in the oil.

 

[cmhj]

When in doubt? Ya too ez

 

[Rand]

Fuel dilution is not water it will not evaporate fully or quickly. It will mix with the oil.

Many of the new DI engines have excessive Fuel dilution compared to previous technology. I expect next-gen oil formulations to address that.

nothing to do with a "loose" spark plug

if your engine isn't showing misfires it is not a spark issue.

 

[bigt61]

You'd have a code if there was a misfire. The engine is still breaking in and rings are seating. IMO rings seat faster with a blend or dino.

 

[Falken]

Change your oil and be glad you didn't need to have a new head helicoiled.

 

[Vikas]

Quote:
Fuel dilution is not water it will not evaporate fully or quickly. It will mix with the oil.
Is this really true? I do know that on its own, fuel evaporates heck lot faster than water! Now I do not know what happens when they mix with oil but if no chemical reaction takes place, then fuel in oil would still evaporate faster than water in oil.

 

[jdavis]

Have you driven it hard? maybe you should (after an oil change)

 

[Danh]

Thanks for the responses; I accept the loose plug probably has nothing to do with fuel dilution.

As to the other points, if I changed oil when a fuel smell was detectable my OCI would be, oh, 500 miles. THAT certainly wouldn't elicit any comments here. And in terms of being driven hard, the current change has about 2,200 miles, 2,100 of which were 75-80 mph interstate cruising and I70 and Hwy 40 passes in Colorado.

Guess a used oil analysis is in my future unless Honda decides to do more than a shoulder shrug.

 

[wemay]

Hi Danh,

Give it 10,000 miles or so. There are many folks who claim the fuel smell goes away after break-in.

 

[Danh]

Originally Posted By: wemay
Hi Danh,

Give it 10,000 miles or so. There are many folks who claim the fuel smell goes away after break-in.


Thanks, wemay. That's a reasonable suggestion, but I'm at 9,200 so break-in should be complete.

Looking around the dealer service department waiting room (which is very, very nice, by the way), it was obvious to me that virtually no one there would know how to check engine oil let alone fret about fuel dilution in direct-injected engines. Ignorance may be bliss after all. They all seemed happy: why do we torment ourselves?

 

[wemay]

Originally Posted By: Danh
Originally Posted By: wemay
Hi Danh,

Give it 10,000 miles or so. There are many folks who claim the fuel smell goes away after break-in.


Thanks, wemay. That's a reasonable suggestion, but I'm at 9,200 so break-in should be complete.

Looking around the dealer service department waiting room (which is very, very nice, by the way), it was obvious to me that virtually no one there would know how to check engine oil let alone fret about fuel dilution in direct-injected engines. Ignorance may be bliss after all. They all seemed happy: why do we torment ourselves?


So ironic you mentioned this. I had the exact same thought last time i was at my dealership's service waiting area.

 

[circuitsmith]

Is it really raw fuel you're smelling, or just combustion byproducts?
They can be similar.

 

[Danh]

Originally Posted By: circuitsmith
Is it really raw fuel you're smelling, or just combustion byproducts?
They can be similar.


They can be similar I guess, but I'd peg it as raw fuel with reasonable confidence. This is new experience for me despite having owned lots of cars including another with DI. Probably do a used oil analysis at the next change and take the results to the dealer if they look odd.