OAI's new fuel dilution reporting

[pb]

in their newsletter from this AM:

Quote:
Extensive studies of oil analysis results over the past few years have shown that, even with traditionally high levels of fuel dilution, most GDI engines will not show an elevation of wear metal levels. This resulted in oil analysis reports that were recommending unnecessary oil changes since there was no mechanical issue or unusual engine wear taking place.

Because of this, Oil Analyzers Inc. has changed the Comments and Recommendations for all gasoline engines flagged for high fuel dilution on a report. The level will still be flagged, but there will no longer be a recommendation to change the oil unless elevated wear metal levels are found or the oil viscosity is greatly affected.


my takeaway from this is: I doubt the metal has changed, thus I am to believe it is the oil that can now live with fuel dilution and not cause increases in metal wear.

 

[wemay]

Excellent share! Thank you.

There have been many instances where comments on a poster's UOA have advised this very same thing. If wear metals aren't affected, no need for change viscosity or worry. It makes sense to me that dilution was and is taken into account by the vehicle manufacturers.

 

[Trav]

What else are they going to say? "Fuel dilution in DI engines is normal and although we know it will prematurely wear the engine out there isn't a thing you can do about it"
I don't think so, if they said that they would take a shellacking from all sides, no one wants to be told they bought a four wheeled commode.

 

[oil_film_movies]

It depends on how much fuel dilution is there, and how thick the basic oil was to start with. Also on which engine model.

Fuel dilution reduces HTHS viscosity, and is not a problem if HTHS is above a certain value specific to your engine.

Bottom line is every engine has an HTHS threshold that, if you go below it, you get a lot more wear. See:

I got those from a friendly_jacek post from 5 years ago, and I have no reference. They are consistent with other studies I've seen over the years.

 

[oil_film_movies]

Looking at the top graph above, one could say that for a lot of engines, HTHS=2.6 is the lowest an engine can handle.
Some engines might be more at a threshold of HTHS=2.0, like some Honda or Toyota hybrids that use the Eneos or Ravenol 0w16 oil that starts out at HTHS=2.4 new.

 

[dblshock]

..and what effect will the excessive crankcase fluid levels have on these TGDI engines? ignore that too?

 

[OneEyeJack]

If you would like to see what an individual did investigating fuel dilution in a high performance engine, investing in having a custom oil formulation made with a lot of time and money spent on oil analysis please search for posts by RI_RS4 about 10 or so years ago. This work includes many track days and a lot of miles commuting. There might be a thousand or more postings by various BITOG members on the subject of RI_RS4's adventure. If you're willing to expend the effort there is a lot of information that you might find interesting.

 

[oil_film_movies]

dblshock, 5% fuel dilution, which is a high one, adds only 1 cup of liquid to a 5-quart sump. That sump there may have been too full in the beginning before fuel dilution.

 

[dblshock]

mine is more like 20-25% based on how the dipstick responds to added fluid... the OA reports stop measuring at 5% from what I understand.

 

[oil_film_movies]

Originally Posted By: DIESELMECH
I have a '12 Ford F-150 EcoBoost. Oil on dipstick shows overfull. Had OA by two different companies both said fuel dilution is too high. Ford says 5-7% is acceptable for this vehicle.

That was an old post. That much fuel dilution is on the high side, to be sure. I'd guess HTHS might drop by 0.5 with that. Better have some margin in the first place. Anybody who suspects fuel dilution (strong gasoline smell from your oil) should start out with one grade higher oil. As in, if you're supposed to use 0w20, start using 0w30... etc.

 

[zeng]

Lowest metal wear rates has always been the 'ultimate' sole determinant in lubrication efficacy.
It's unfortunate to tribology fraternity, the 'ultimate' focus on metal wear rate ...
has been lost and sidelined by secondary consequential parameters like fuel economy, emissions etc.

Advancements achieved thus far in modern day additive package, has almost relegated unfavourable fuel dilution and oil viscosity increment phenomenon as non-issue in the context of metal wear reduction.

 

[Danh]

DI/TGDI engines have been around for enough time to have lots of high-mileage examples out there. And despite fuel dilution, the biggest offenders (Ford EcoBoost, Honda, Kia/Hyundai) haven't had a rash of engine problems other than the manufacturing debris issue afflicting Hyundais and Kias.

Looking around the waiting rooms of my Honda and Acura dealers it's abundantly clear that these cars are receiving no special attention and 99+% of owners have no idea what fuel dilution means. And the service advisors, who should be aware of premature wear/failure issues, advise frequent oil changes only to get more service revenue.

The durability bottom could still fall out for these engines but it just may be the manufacturers have this right. The graphs provided suggest wear from fuel dilution comes at higher rpms, so maybe the ultra-low operating revs most modern engines are protective. It still makes me uncomfortable and I wish I could see my way clear to using a 30 weight oil instead of the spec'd 20, but I just may join the uninformed masses and not worry about it.

 

[dblshock]

well the turbo will doubtfully tolerate compromised lube at 200k rpm for long.

 

[Danh]

Originally Posted By: dblshock
well the turbo will doubtfully tolerate compromised lube at 200k rpm for long.


Well then, Honda's going to have one heck of a warranty or reputational as problem in a few years as these things begin to explode in the hundreds of thousands.

 

[kjbock]

Originally Posted By: Danh
Originally Posted By: dblshock
well the turbo will doubtfully tolerate compromised lube at 200k rpm for long.


Well then, Honda's going to have one heck of a warranty or reputational as problem in a few years as these things begin to explode in the hundreds of thousands.


I believe Honda said they have sold over 500,000 of the new generation Civic and I imagine the take rate on the turbo engine is probably 50% or more, plus it is in every new CRV that they are selling 20-30,000/month. I would expect Honda tested the [censored] out of this engine before release on such an important high volume application.

 

[ChrisD46]

A lot of good points here ! My 2017 Hyundai Sonata 2.4L GDI (non-turbo) engine is spec'd for 5W20 . Dealer uses bulk (probably QS) 5w20 syn blend and recommends 3K ~ 5K OCI for city / suburban driving conditions . I did the 1st oil change at 1,500 miles with 5W20 Pennzoil Gold and the fuel dilution was quite evident while changing the oil (heavy fuel smell). Now at 5K miles with the dealer oil change and monitoring dip stick for fuel smell , change in capacity , etc. I wanted to have a record of my car's 1st service with the dealer but plan on doing oil changes myself with M1 10W30 . Why this oil ? I live in the North Georgia where the temps rarely get below 20 degrees F. and a 10W syn is good down to 0 degrees F. (and approved by Hyundai). My other reasons for the M1 10W30 are due to the GDI engine design where M1's lower calcium helps guard against LSPI (i.e. pinging) while the 10W30 weight has the lowest NOACK and lowest VII's which help guard against intake valve deposits (top tier fuel used as well) . Finally , I don't let the engine lug and take it out on the H'way once every few months for a run at 4K RPM's for 20 minutes (i.e. Italian tune up) and you will have done all you could to have a trouble free GDI engine (turbo or non-turbo) .
Originally Posted By: Danh
DI/TGDI engines have been around for enough time to have lots of high-mileage examples out there. And despite fuel dilution, the biggest offenders (Ford EcoBoost, Honda, Kia/Hyundai) haven't had a rash of engine problems other than the manufacturing debris issue afflicting Hyundais and Kias.

Looking around the waiting rooms of my Honda and Acura dealers it's abundantly clear that these cars are receiving no special attention and 99+% of owners have no idea what fuel dilution means. And the service advisors, who should be aware of premature wear/failure issues, advise frequent oil changes only to get more service revenue.

The durability bottom could still fall out for these engines but it just may be the manufacturers have this right. The graphs provided suggest wear from fuel dilution comes at higher rpms, so maybe the ultra-low operating revs most modern engines are protective. It still makes me uncomfortable and I wish I could see my way clear to using a 30 weight oil instead of the spec'd 20, but I just may join the uninformed masses and not worry about it.

 

[doyall]

Originally Posted By: Danh
... The durability bottom could still fall out for these engines but it just may be the manufacturers have this right. The graphs provided suggest wear from fuel dilution comes at higher rpms, so maybe the ultra-low operating revs most modern engines are protective. It still makes me uncomfortable and I wish I could see my way clear to using a 30 weight oil instead of the spec'd 20, but I just may join the uninformed masses and not worry about it.


I see it as the manufacturers do not necessarily "have it right" but are taking the far much better than average risk that the typical customer will not operate the vehicle in a fashion that will exacerbate the problems known to be caused by excessive fuel dilution. This is where my problem comes in: the manufacturers are placing in the stream of commerce products that the engineering community deems to be operating outside of generally accepted design operating parameters. They essentially sell automobiles that do not conform to their express warranties. Engineers tend to place the upper limit of non-critical fuel dilution at 5%. I would be willing to bet that the typical low-mile-commuter/grocery-getter GDI or TGDI engine runs with significantly over that percentage the vast majority of OCI time. I challenge you to find a manufacturer who will state that their engine is designed to operate problem-free with 7, 8, 9% fuel dilution. To safely run under all conditions with that much fuel in the oil would require some proprietary metallurgy that defies the laws of physics. I do not think such an engine exists. Manufacturers are betting there will be minimal problems during the warranty period due to the overwhelming low stress nature of operation. Just because that bet is paying off doesn't mean that they have it right. It suggests to me that the manufacturers are bamboozling their customers and intentionally selling non-conforming products. High fuel dilution combined with the staggering amount of electronics in modern automobiles is why I have developed the mindset that I will no longer be in an automobile that does not have an extended service contract with it. Would probably go to leasing if I could convince the wife of it.