How have fuel dilution issues changed oil change intervals

[2.7ecoboostFordBronco]

There’s no clear answer to the questions. The accepted mitigation for fuel dilution over about 3% is to go one grade higher and shorten change interval. Whether the grade increase is better than the interval reduction is up for debate as far as I have read.

Savant labs says over 2.4% “requires attention”.
Polaris considers over 3.4% “abnormal”.

The problem is that some engines seem to routinely operate over 3%, especially turbocharged and/or direct injected engines. This level of dilution seems to occur almost immediately on the first few starts after an oil change on some engines, especially in cold weather. Hondas, some Ford Ecoboosts, and Subarus come to mind.

If the mitigation were to change the oil at 3%, you’d be changing the oil near everyday with some makes. So I would be inclined to up the grade and keep the interval around 5,000 rather than excessively shorten the interval, as there is a slight wear increase at the beginning of every oil change and always the slight risk of a maintenance induced failure.

There is also debate about whether manufacturers accounted for dilution when specifying a grade for their engines. For instance the Ford 3.5L ecoboost originally specified a 5W-20 when launched in 2010 but was upped to a 5W-30 in subsequent years perhaps due to observed fuel dilution in the field, but that is speculation. Further it has been reported here that significant wear increases from fuel dilution have not been observed in studies until levels nearing 10% (4th hand info from SWRI-HPL-SubieRubieRoo-Me). 5% was mentioned by HPL as a condemnation point (change the oil). I have hit that in as little as 900 miles during cold winter months.

 

[S62MPOWER]

An analysis will determine your next move. Short trips in a Winter environment is "severe service" as described by your manual. I would think 2X year with an oil that is resistant to shear and resistant to oxidative break down to counter your fuel dilution would be a good choice (Current Favs for these attributes, without going boutique oils here on bitog are I think Mobil 1 ESP 0W30 or 20) or Pennzoil Ultra Platinum. Both would work without an analysis for 2X/yr oil changes with very little risk. Also, use Top Tier gas and use a bottle of Techron Total Fuel System Cleaner, RL Si-1 or the New Valvoline Restore and Protect Fuel System Cleaner a few tanks of gas before your oil change or 2X year. This should reduce the chances of the injectors being dirty and the cause of the fuel dilution. You have so few miles though, it is unlikely, still, ethanol in the fuel, cold starts, direct injection, it is what it is. Take a 25+ minute spirited drive now and again, it will burn off fuel and cleanse the soul. : ))

 

[Patman]

Take a 25+ minute spirited drive now and again, it will burn off fuel and cleanse the soul. : ))

Driving for a long time doesn’t burn off the fuel that gets into your oil. Once fuel gets in there it is there to stay, no matter how much highway driving you do.

 

[kschachn]

An analysis will determine your next move. Short trips in a Winter environment is "severe service" as described by your manual. I would think 2X year with an oil that is resistant to shear and resistant to oxidative break down to counter your fuel dilution would be a good choice (Current Favs for these attributes, without going boutique oils here on bitog are I think Mobil 1 ESP 0W30 or 20) or Pennzoil Ultra Platinum. Both would work without an analysis for 2X/yr oil changes with very little risk. Also, use Top Tier gas and use a bottle of Techron Total Fuel System Cleaner, RL Si-1 or the New Valvoline Restore and Protect Fuel System Cleaner a few tanks of gas before your oil change or 2X year. This should reduce the chances of the injectors being dirty and the cause of the fuel dilution. You have so few miles though, it is unlikely, still, ethanol in the fuel, cold starts, direct injection, it is what it is. Take a 25+ minute spirited drive now and again, it will burn off fuel and cleanse the soul. : ))

I'm not sure what a shear resistant VII does to help here. Does the OP have a problem with mechanical shearing?

And oil brand is not as relevant as increasing the grade and lowering the OCI.

 

[spasm3]

Take a 25+ minute spirited drive now and again, it will burn off fuel and cleanse the soul. : ))

Nope, my recent UOA was after a 30-40 minute drive. Fuel dilution came back at almost 3 percent.

 

[kschachn]

Nope, my recent UOA was after a 30-40 minute drive. Fuel dilution came back at almost 3 percent.

It also has to do with why the fuel is there in the first place. Some people seem to think that the fuel only gets there once under some set of circumstances and then you can drive it off, when the problem is that it's being introduced in a more continual basis.

 

[GI_GRIFF]

This should reduce the chances of the injectors being dirty and the cause of the fuel dilution. You have so few miles though, it is unlikely, still, ethanol in the fuel, cold starts, direct injection, it is what it is. Take a 25+ minute spirited drive now and again, it will burn off fuel and cleanse the soul. : ))

On my last vehicle, which was a 2015 Honda CRV with the 2.4L naturally aspirated (no turbo) engine, it had red flag fuel dilution according to Polaris. It had 5200 miles on the service, around a year of time on it. I took it in when the maintenance minder had 10% service life left on it. Honda did a bunch of testing on it and re-programed the ECM. Everything they did made no difference as far as the fuel dilution goes. That engine in that Honda, and most gas engines these days are built with low tension piston rings, basically built on purpose to reduce piston drag and have blowby from the factory brand new. I don't disagree with you here, but I just wanted to point out the low-tension piston rings contribute to the problem too. I think a higher viscosity thicker oil, and a low Noack oil could help. I am having the same fuel dilution issue with my 2025 Toyota Rav4 no turbo, non-hybrid engine. It just does short trips around town though, rarely gets out to stretch its legs. I have decided to go 3000 miles or 6 months, whichever comes first on this vehicle. Toyota requires a 6-month OCI severe service schedule on it. I am using a 0W-30 engine oil in it. The manual says to use a 0W-16. The car sounds better with the 30 weight and I can't see any visible increase in my gallons burned (mpg) when fueling up. Just my 10 cents.

 

[GaryMX5]

I appreciate everyone's comments and recommendations. My initial thought is to initially stick with a 5K oci but to also change at 6mos (whichever occurs first). The latter I, admittedly, was not giving much attention too and would often stretch out. It's quite clear that short tripping over time has as much impact as mileage alone. I'm also giving serious consideration to bumping up to 5w30 to further address dilution impacts.

 

[Hohn]

No harm in going to 3k OCIs.



Let's not go there. "Upping the viscosity" is the kind of crazy talk that will have your children put you in a home sooner.



I'm a geezer, too. Just a couple of car lengths behind you.

I’m in my 50s and using 40 grades in my vehicles specifying 0w-20. With superb results.

 

[shortyb]

Do you change your own oil or have it done somewhere? DIY? go up to at least a 30wt., 0 or 5W (I like Mobil 1 ESP 0W-30), every 6 months regardless of mileage (unless over 5K) and enjoy the Zen of getting all up close and personal in all that oily goodness .

For fun, get a good UOA (NOT Blackstone, if gauging fuel) done to see where your dilution numbers are and adjust from there if necessary.

 

[shortyb]

I’m in my 50s and using 40 grades in my vehicles specifying 0w-20. With superb results.

I like this way to go too.

 

[tig1]

Is your Ford Fusion a 2.5 ? If it does, its port injected.

You don't have Direct Injection so naturally you would not have the fuel dilution results that some DI engines do.

Now your gettin it! That's why I won't own a DI turbo engine.

 

[spasm3]

Now your gettin it! That's why I won't own a DI turbo engine.

My DI mazda is not turbo.

I agree, but good luck on your next new vehicle. Almost everything is DI.

 

[Magnumdude]

I have a 2018 GMC 1500 with the 6.2. I could smell the fuel in my catch can. I run short OCIs because I have a mental disorder that causes extreme anxiety that increases exponentially the farther over 2500 miles I let my OCI get.

 

[altaylar]

I’m in my 50s and using 40 grades in my vehicles specifying 0w-20. With superb results.

Going a grade higher is a comman practice around here, even without any fuel dilution concerns.

With fuel dilution concerns, it is more than warranted.

And as a general rule, I would conaider Mobil 1 0w40 to be of of 30 grade, since it is soon after it is poured in