Is the oil dilution theory some BS?

[tamamade]

I've read somewhere that someone's saying you must change your oil every 5k, because the gas will blow past oil ring and dilute the oil.

Sounds terrifying. Ford engineers didn't realize this when they design the engine?

Plus, if you think hard, even if some gas do get into the oil, what will happen?

Gas can dissolve in oil, of course. They are all hydocarbon molecules.

But, gas has a very low evaporation temperature compared to oil. If some gas do get into oil, at the normal engine temperature (which is well above 190 degrees), gas will evaporate. So the minuscule amount of gas mixed in the oil will be gone in a second.

Thats why gasoline is called gas, because it's turning to gas so easily in room temperature, not to mention the high engine operating temperature.

Just some thought.

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[GPSMan]

I've read somewhere that someone's saying you must change your oil every 5k, because the gas will blow past oil ring and dilute the oil.

Sounds terrifying. Ford engineers didn't realize this when they design the engine?

Plus, if you think hard, even if some gas do get into the oil, what will happen?

Gas can dissolve in oil, of course. They are all hydocarbon molecules.

But, gas has a very low evaporation temperature compared to oil. If some gas do get into oil, at the normal engine temperature (which is well above 190 degrees), gas will evaporate. So the minuscule amount of gas mixed in the oil will be gone in a second.

Thats why gasoline is called gas, because it's turning to gas so easily in room temperature, not to mention the high engine operating temperature.

Just some thought.

Not 100% of the gasoline liquid will evaporate. Only about 80-90%. There are "heavy" molecules mixed in with the volatile "light" molecules. Gasoline is a mixture. Not a molecule.

 

[tamamade]

Not 100% of the gasoline liquid will evaporate. Only about 80-90%. There are "heavy" molecules mixed in with the volatile "light" molecules. Gasoline is a mixture. Not a molecule.

Then you need to explain to me why 2 months after I did the oil change my dipstick mark has not gone up. If there's any significant dilution there should be more oil/liquid whatever, right?

 

[GPSMan]

Then you need to explain to me why 2 months after I did the oil change my dipstick mark has not gone up. If there's any significant dilution there should be more oil/liquid whatever, right?

Dude...

It CAN happen. That does not mean it IS happening right now.

Also, you can put, ummm, 10 tablespoons of sugar in your tea and the level won't go up either.

In my school they offered a Chemistry class.

 

[tamamade]

Dude...

It CAN happen. That does not mean it IS happening right now.

Also, you can put, ummm, 10 tablespoons of sugar in your tea and the level won't go up either.

In my school they offered a Chemistry class.

sugar dissolves in tea. The volume will not change. gas mix with oil, it will increase the volume.

 

[GPSMan]

You asked a question. You have an answer. In 3 or 4 hours you will have the same answer 10 or 12 times.

 

[RobertD]

Oil dilution has become a more noticeable problem since direct injection has become popular with the manufacturers.

Oil dilution is at its worse on a cold start up. When the engine is cold and just starts up the direct injection will spray a rich mixture of fuel directly into the cylinder and a little bit of the fuel will stick to the cold cylinder walls. Also at this time the piston, rings and cylinder walls have not come up to operating temps and there will be small gaps in the rings that will allow the fuel to get by and get in the oil.

If you are like me and live in the south where the temperatures are warmer it will lessen the effect. When I went to Pennsylvania in a blizzard I checked my oil after just driving to a gas station and it had a strong gas smell that I never had before or since.

Also If you are like me and rarely drive frequent short trips back to back, your engine will appreciate getting up to temperature and burning off the fuel in the oil.

It is common for folks who make frequent short trips in the northern states to experience heavier fuel dilution and actually see their oil levels rise.

It is effects all brands of vehicles. All engine designers are aware of the issue including those that work for Ford. They have been improvements in material science that help and in the engine design but the problem is not so simple to solve. EPA is mandating stricter cafe (mpg) and emission requirements that drive manufacturers to add in systems like direct port injection to meet the ever more demanding requirements. However there are always trade offs in design issues. Engine power and longevity and EPA requirements have been a weird love / hate relationship. If you remember the mid 70s and 80s you will know what I am talking about.

FYI, Honda owners seem to have it a little worse with fuel dilution or they are just the most vocal on the internet.

Engine designer have also been working with Oil designers to come up with additives that help fight the negative effects of fuel dilution of the oil.

Should you change your oil every 5,000 miles not necessarily, you can go with the factory recommended intervals or extend it out to never changing your oil. Or you can change it every day if you wish. Somewhere between every day and never is a good balance of clean oil, engine longevity, cost, convenience, etc. For me I tend to use a good oil filter and full synthetic oil and change at 5K intervals. For some reason engines tend to last longer for me than the for most folks. However you do you.

 

[RichardCranium]

sugar dissolves in tea. The volume will not change. gas mix with oil, it will increase the volume.

If you add matter to matter, volume increases. That is chemistry. Dissolving something will increase the volume, but since sugar molecules are smaller than sugar solids, when you dissolve sugar in a liquid, the volume of the sugar decreases and thus does not cause the level of the liquid to rise as much.

new engines should not have much piston ring blow by. As engines wear, that increases.

the reason your oil level is not increasing, if you do have excessive blow by, is because of your EGR system. The gas that does get past your engine rings is still a gas, and that gas is vented from your engine block back into your combustion chamber. The EGR system helps keep your oil from getting contaminated by those gases and other gases that are released by engine oil when it is heated

 

[LM42]

sugar dissolves in tea. The volume will not change. gas mix with oil, it will increase the volume.

What in the heck are you even asking, and where the eff did you read that? Some of the questions on here boggle my mind. There is some stuff that passes the rings. This happens on literally every combustion engine ever made. It is not inherently a problem. There can be failures like an injector sticking open, or an actual ring failure that can make the problem much worse, but both are rare. Why concern yourself with such nonsense on a brand new vehicle?

 

[Mightybeast]

On personal thought I think that if Ford up provides you with information sach as change oil every 10k miles or once a year, or what ever comes first is a try statement. As a reference I used vehicle manual or Ford app

 

[Rivers90]

More of a problem if you do lots of short trips and the oil does not get hot.

 

[Montana]

WTF am I reading?

 

[Flomounier1]

Only one way to find out. Someone needs to test the viscosity of oil at 10k and 5k.

 

[RedRider]

You need to have a serious misfire, broken rings, and incredibly worn 800k-mile cylinder or a stuck injector to have any measurable amount of fuel in your oil at all. All of these would cause engine fault codes long before your oil became slightly polluted. So, if you are not seeing the check-engine light, there is no cause for concern whatsoever. You've been reading too much fear mongering from someone who does not understand how any engine built in the last 55 years actually works.

 

[NoVaJimmy]

I've read somewhere that someone's saying you must change your oil every 5k, because the gas will blow past oil ring and dilute the oil.

Sounds terrifying. Ford engineers didn't realize this when they design the engine?

Plus, if you think hard, even if some gas do get into the oil, what will happen?

Gas can dissolve in oil, of course. They are all hydocarbon molecules.

But, gas has a very low evaporation temperature compared to oil. If some gas do get into oil, at the normal engine temperature (which is well above 190 degrees), gas will evaporate. So the minuscule amount of gas mixed in the oil will be gone in a second.

Thats why gasoline is called gas, because it's turning to gas so easily in room temperature, not to mention the high engine operating temperature.

Just some thought.

I have posted lab results via a used oil analysis which showed 2.2% fuel dilution which correlates to a degradation of both viscosity and flash point. What you're saying is based on assumption unfortunately rather than science. Also, fuel dilution is very dependent on driving style and driving conditions for each individual. What I do suggest is getting a used oil analysis based on oil in YOUR vehicle to determine if your driving style and conditions causes excess fuel dilution rather than making assumptions.

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