Does fuel dilution reverse?

[mjoekingz28]

Im under the assumption that the reason for a short OCI when making short trips is because of fuel dilution.

Since May I've been doing alot of 2 mile trips (should've been riding my bike, but anyway) and now Im making a 220 mile trip 1-2 times a week.

So, will the oil go from bad (short trips) to good by taking long trips.

Basically, I went from a severe duty to a normal or non-severe driving pattern. Has the damage been done already or is it reversible?

 

[d00df00d]

You should probably change your oil soon just to be safe. Long trips do help cook fuel (and water) off, but a lot of time has passed so the fuel has probably done its work by now.

 

[Gary Allan]

I can't speak intelligently on the topic, but I seem to recall that you can flash off about 50% of the raw content at normal oil temps fairly quickly, but that the remaining residuals are more stable.

 

[FZ1]

Doesn't reverse. Dump it out.

 

[mechtech2]

Short trips are bad for oil primarily from moisture contamination, not fuel.
Fuel injected cars are quite precise nowadays.
Fuel evaporates quickly by itself -especially with heat. When mixed with oil, it is much slower to go away. In either case, there are small residuals that are harmful.

 

[gfh77665]

Originally Posted By: mechtech2
Short trips are bad for oil primarily from moisture contamination, not fuel.
Fuel injected cars are quite precise nowadays.


Thats correct. EFI beats the old carb systems greatly.

 

[labman]

I suspect the first 220 mile trip boiled off most of the gas and water. However, the acid may have eaten all your TBN reserve. Sludge could be a problem too.

 

[artificialist]

Originally Posted By: gfh77665
Originally Posted By: mechtech2
Short trips are bad for oil primarily from moisture contamination, not fuel.
Fuel injected cars are quite precise nowadays.


Thats correct. EFI beats the old carb systems greatly.


EFI gives a more precise air/fuel mixture than a carb, and atomizes the fuel much better.

However, EFI or carb, cold engines need an enriched air/fuel mixture, so in either case, short trips lead to higher fuel contamination. The other problem is that cold engines tend to burn fuel less efficiently because once the combustion flame reaches the cold head and cylinder wall, it is extinguished. The will problem be smaller with EFI, but it will still be an issue.

 

[mechtech2]

I just want to repeat that I said short trips are bad for oil PRIMARILY because of moisture contamination.
Fuel is certainly a factor.
I have seen umpteen jillion engines, and moisture in the oil and valve cover are way more common than fuel in the oil.

 

[Rand]

Originally Posted By: mechtech2
I just want to repeat that I said short trips are bad for oil PRIMARILY because of moisture contamination.
Fuel is certainly a factor.
I have seen umpteen jillion engines, and moisture in the oil and valve cover are way more common than fuel in the oil.


and you do continuous uoa testing of these said engines while driving to see the fuel in the oil?