i'm always using the Mobil 1 extended.

 

Here are some July 2007 comments regarding fuel dilution, from the owner of Dyson Analysis:

"..........Most newer cars are using a fuel map schedule that is designed to flush or wash out NOx emissions by a delicate balance of a metered "puff" of fuel being introduced. This has a physical liquid washing effect while lighting off the healthy properly working 3 way CAT and gaining excellent emissions reductions. However, if the design is not quite perfected or there is ANY other variable that throws the schedule or combustion chamber seal off you end up with what most are seeing as excess fuels or aromatics in the sump motor oil.

Honda was the first to try this and all are following.

Depending on the chemistry of the fuels it can have BOTH permanent and temporary damage effect on the host motor oils. It is very complex and hard to measure................................Many of the purported top of the line "synthetics" are terrible at resisting the aromatics attack. No names mentioned but M1 is the worst offender in current formulation. And the main reason for their UOA wear values being higher particularly in iron readings...........................

Some motor oils have successfully reformulated to take advantage of the fuels realities here in the US. Some have not.........."

"...........XOM is underdeveloping and underexecuting on their top of the line formulas and commentary to the opposite is poppycock. In a normally running engine M1 will work fine but the current formulas indeed allow too much wear by any measure. Aromatics from systemic fuel dilute is causing aggravated wear in most oil formulas but M1 is letting YOU the customer down for the money spent. You are paying for brand recognition not technology. Hopefully that will change.... they sure have the resources to do it........"

http://www.bobistheoilguy.com/forums...951743&fpart=1

 

Just a thought, but is everyone with these high levels of fuel dilution in cold weather climates? Anyone in a warm or mild winter season still showing high levels?

 

Good news! I got my Blackstone Labs oil analysis back and had < 0.5% fuel dilution with about 2000 miles on the oil. Completely stock Evo X with Mobil1 5W-30. The oil did smell like fuel noticeably (especially after driving), but here is part of their analysis. This seems to imply the fuel smell may be normal, and also seems to explain why some of the other reports posted show that fuel dilution can increase and decrease over the life of the oil change interval:

"The flashpoint was normal here, so we doubt fuel dilution is an issue for you at this point. The viscosity was low and this likely shows some fuel was getting into the engine, however, when the oil gets hot, that fuel should evaporate and since we didn't find any here, we think that process is working correctly."

SUS Viscosity @ 210F = 52.5 (should be 55-62)
cSt Viscosity @ 100C = 8.1 (should be 8.8-11.1)
Flashpoint in degrees F = 370 (should be > 365)
Fuel % = < 0.5 (should be < 2.0)

Should I be concerned about the low viscosity? What would this oil equate to (e.g. 5w20 instead of 5w30)?

I'd highly recommend others getting oil analysis done. I personally like Blackstone because their analysis includes comments on the results that are easy to understand. Maybe we can find some more stock X's with normal fuel dilution. BTW, I'm in a somewhat cold climate (overnight lows in the 20's, daily highs in the 40's-50's most of the time).

 

Good news indeed. I got my kit a day ago, and forgat to saved the old oil. So it will be a while for results from me

 

Yes, it is a 5W20. See viscosity chart here:

http://www.bobistheoilguy.com/index....d=48&Itemid=55

Did you take a long drive immediately before taking the oil sample?

 

Well, as with everything, there is good news and bad news: The Good News-low % fuel dilution; the Bad news-still got vicosity drop from 30W to 20W. It is the lose in viscosity that is of concern because of the reduction in lubrication. In addition, these data demonstrate that a low % fuel dilution does NOT necessarily mean there is little fuel entering your engine oil. As indicated earlier, this is because % fuel dilution is a dynamic variable not a cummulative one.
I do want to thank you for providing the average highs and low temperatures which were experienced over the oil cycle; it is beneficial (please see post below)and we need to document this in Giz's xls spreadsheet.

Later, Ken

 

Talked with Chris Black at AMS recently and, with his permission, would like to share his thoughts on this issue after his review of our 4 data points (not NMX's which was submitted after discussisions with Chris).
Chris's comments were similar to those acquired from AMS and presented by Rancornthree (see post earlier) and were:
(1) Break in for young engines will slip fuel and wear variables will be higher than engines with higher number of miles
(2) Excess idle will increase fuel in oil
(3) Use of a wideband to establish the level and conditions of low A/F
(4) Weather conditions vis., temperature during oil cycle
(5) Efficacy of M1 questioned (as well as Dyson labs as per Sub earlier) and suggested use another syn, AMSOIL SSO
(6) Engine wear variables and levels/concentrations may be engine specific. For example, the acceptable level of Fe and Al < 30ppm may not be "universal" wear levels as per John Browning (see earlier post).
(7) Mitsu's TSB and oil dilution, Chris said, "...if no-one is beating on the car when it is below full coolant temp, then the TSB should not apply."

Some Q&D thoughts on the above and earlier Posts:
Earlier EVO owners noted (as per Rancornthree post), albeit their noses, fuel in engine oil and Sbluro noted there has not been a single analysis performed on 4G63T. That said, the aluminum alloy pistons and iron sleeve and ring configuration of the VII and IX are similar to X so it is not unreaseanable to assume that this fuel entry has been with Mitsu engines for some time.
As to causes for the fuel entry, we have Dyson Labs suggesting deliberate fueling to reduce NOX emmisions resulting in excess fuel in cyclinder and eventually sliping into oil if there is ".... any other variables that throws the scheme or combustion chamber seal off...". Now the question is what are these "other variables"? For me, one is definitely temperature. Mitsu.'s TSB has stated that excess fuel will enter the engine oil under warm up conditions IF the engine is under boost. Chris and Mitsu is saying that this will occur ONLY under these conditions. But is this true? Could not excessive amounts of fuel also enter during this period even when one is driving w/o boost especially when you have metal, Al alloy that has twice the expansion rate of steel. So during warm up the piston and rings are at there smallest dimensions and you have a rich fuel mixture being added, it is possible, no likely, that an excessive amount of fuel is sliping through to the engines oil. Now let's add the geographic region as a variable and consider two X's, one in Calgary (-35F) and the other in Miami (70F) in the winter starting and stopping say 4 times over the day and travelling 40mi and three short trips. I am suggesting that the %fuel dilution or more accurately the viscosity lose in Calgary would be >>> Miami.
Bottom Line: Monitoring-For those that submit or have submitted their oil analysis, I think we also need to have (1) the highs and lows temp for the oil change cycle (2) rough estimate of the number of warm up cycles experienced in same. For if the above cause for fuel entry proposed above is correct, then we should see a definite relationship between these variables.
Now you say, I don't give a dam about this. What do I do now to protect my engine? Answer, what has already been proposed, namely change from M1 to some of the other better (in sence of wear protection) synthetics, do not idle the car when cold, just drive it but no boost, light load and during the winter try to minimize the number of cold starts by being more efficient in your travel plans.
Finally, we need to see if these actions actually work by checking and reporting on the state of your oil through analysis. Sorry this went on for so long!

Later, Ken

 

My sample period was from Oct-Dec 31. That means average high/low temps of 55/35 in October, 40/25 in November, and 35/20 in December. I start the car about 5 times a day. Warm up idle is minimal- approx. 15 seconds. I would estimate 450 start-ups on my sample.

I am really curious what the analysis will show on my current oil. It has been very cold lately: several weeks of temps that did not reach 20 and were often single digit and below. Only have 250 miles on this oil, so it will be awhile before we find out.

 

Having a 5w20 can't be good. This was with only 2k miles over a 3 month period. I am sticking to 3 month cycles. Also, I did not take a long drive before the change. Probably had the car on for about 5 minutes of low speed stop/go driving (max speed limit was 30 mph).

My typical routine is 2-3 startups per day (so estimate about 180-270 startups) and I warm up about 30 seconds before driving off gently to get the car up to temp. Also have both factory flashes on my completely stock X.

 

I got mine changed yesterday, 3000 miles on the oil. Sending a hot sample (pulled right after my 50 mile commute) to Blackstone today. Will post results and conditions when I get the report back. Also AP flashed my car right after oil change, so next change sample should give a stock vs tuned comparison.

 

Here is an UOA from an EVO VIII:

http://www.bobistheoilguy.com/forums...ue#Post1247401

 

The fact that you took only a 5 min drive before oil sampling is a worst case scenario for high fuel dilution. That you still had very low fuel dilution in your UOA after such a short drive should be reassuring.

If you want to stick with a 30 weight oil, those that would be called "heavy" 30 weights would be German Castrol 0W30, and Shell Rotella T 10W30. Their starting viscosities are at the high end of the SAE30 classification, and they may be less prone to end up as a SAE20 after 2000 miles.

And if they also end up as SAE20 after 2000 miles, then maybe a switch to 0W40 or 5W40 oils would be advisable.

 

Thanks Sub for looking this up. Am I correct that the oil viscosity in this 4G63 engine is in the 20W range rather than the desired 30W? If true, then these results are similar to NMX's, namely, %fuel dilution low/acceptable range but viscosity has been compromised. Second, interesting why Pb is high, again above Browning's 15ppm criterion, but yet Al and Fe are low. So do these data suggest the viscosity decrease is associated with higher bearing wear?

Later, Ken

 

Ken, I think his high lead was mostly from the use of Torco additive. Other bearing wear markers (tin, copper, silicon) were low, so I think it was lead contamination from the Torco. Yes, his oil is now a 5W20.

Keep in mind that his fuel may be higher than the reported 1.3%. Blackstone uses the "open cup" flash point protocol to measure fuel. This protocol mostly measures (indirectly) the "light end" gasoline fractions in the oil. His oil may be heavily contaminated with "heavy end" gasoline fractions, but they would not show up in the open cup flash test. And if he drove his VIII for an hour before taking a sample, this will boil off a lot of the light end fractions, and give him an artificially low %fuel in his UOA.

From oilanalysis.com:
".....Because there is often some overlap of the light-end volatile constituents of some lube oils with the heavy ends of the fuel, the presence of fuel dilution may be less distinct. This is particularly true when all of the fuel dilution is the result of blow-by, i.e., fuel entering the crankcase by way of the combustion chamber. In such cases only the heavy ends may enter the oil with the oxidized light ends as a part of the exhaust gases. However, in the case of leakage of raw fuel, including dribbling injectors, all or a high percentage of the fuel light-ends can be blended with the crankcase oil. Another influencing factor is that hot running crankcase temperatures alone are often sufficient to boil off light-end fuel fractions, leaving the less volatile and more viscous heavy-ends mixed with the oil and potentially undetectable with the flash point test..."

http://www.oilanalysis.com/article_d...up=Maintenance

Peter