Fuel Dilution - FAQ

[StevieC]

 

[Ducked]

Goes on a bit. (fuel dilution) "is why the service interval has a time limit as well as a mileage limit" (probably not an exact quote but close enough) doesn't appear to make sense.

 

[StevieC]

Excessive idling / stop-go traffic. Low miles but high fuel dilution because of lots of injection cycles and/or low temps not heating the oil enough to evaporate some of the fuel.

 

[Ducked]

Originally Posted By: StevieC

Excessive idling / stop-go traffic. Low miles but high fuel dilution because of lots of injection cycles and/or low temps not heating the oil enough to evaporate some of the fuel.

I dunno. Are low miles necessarily, or even generally, slow miles? I was thinking of my own situation, where the car is mostly recreational use so infrequent but gets up to temperature when it is used.

 

[StevieC]

It really depends on what temperature the oil reaches and for how long to help evaporate the contaminants. Then if it spends more time idling than actually moving then that is a factor as well as my first point.

 

[ZeeOSix]

That guy's a bit "snotty" ... Guess he thinks that gets subscribers.

 

[StevieC]

He is cranky for sure....

 

[4WD]

I could not even finish ~ don’t think I’d send him a question and then sit and hear it mocked like a school boy …

 

[Eddie]

I would like to see some REAL data that plots % fuel vs wear. Based on 5 or so UOAs I've seen showing fuel dilution of 1 to 3% I've observed no real increase in wear. I think some of us get paranoid over the idea of fuel dilution. Ed

 

[andyd]

In the norm, from reading UOAs, fuel < 1%. Fuel dilution was a major deal with carbs and chokes. In a modern car, its a non-problem.

 

[StevieC]

Originally Posted By: andyd

In the norm, from reading UOAs, fuel < 1%. Fuel dilution was a major deal with carbs and chokes. In a modern car, its a non-problem.

I think lubricants have improved in this regard as well since then as well.

 

[Danh]

Originally Posted By: andyd

In the norm, from reading UOAs, fuel < 1%. Fuel dilution was a major deal with carbs and chokes. In a modern car, its a non-problem.

You're likely reading UOAs from Blackstone, which are not reliable for gauging fuel dilution. Look at Oil Analyzers/Polaris UOAs instead, which uses gas chromotography for this purpose. On Blackstone UOAs ignore fuel dilution and look at viscosity instead: you'll see lots of samples below or nearly below grade. Fuel dilution is an issue withnDI/TGDI engines; the question is how harmful it is. But when you hear reports of increasing sump levels it can't be a non-problem.

 

[Balrog006]

Originally Posted By: Danh

Originally Posted By: andyd

In the norm, from reading UOAs, fuel < 1%. Fuel dilution was a major deal with carbs and chokes. In a modern car, its a non-problem.

You're likely reading UOAs from Blackstone, which are not reliable for gauging fuel dilution. Look at Oil Analyzers/Polaris UOAs instead, which uses gas chromotography for this purpose. On Blackstone UOAs ignore fuel dilution and look at viscosity instead: you'll see lots of samples below or nearly below grade. Fuel dilution is an issue withnDI/TGDI engines; the question is how harmful it is. But when you hear reports of increasing sump levels it can't be a non-problem.

Why not? Increasing to what level? Slight increases aren’t any cause for concern-just like normal slight overfills aren’t, but I’ve yet to see any pictures of major increases in overall sump volume reported here.