Patman

After doing my first oil change on Sunday, as usual whenever I do oil changes on my cars, I collected a sample for analysis, and here are the results for my 2018 Corvette, analysis done by Wearcheck Canada:


1,111 miles on oil
Nov, 2017 to Mar 3, 2018 (4 months)
1,111 miles on engine
Mobil 1 5w30 (factory fill)
AC Delco PF64 oil filter
7 quart oil capacity
No make up oil



Iron 48
Lead 2.7
Aluminum 3.5
Copper 36
Chromium 0.8
Nickel 0
Titanium 0
Tin 0.8
Silver 0
Vanadium 0

Silicon 124
Potassium 6.2
Sodium 4.5

Moly 151
Boron 82
Barium 0.3
Calcium 1217
Magnesium 446
Manganese 2.1
Antimony 1.4
Lithium 0.3
Beryllium 0
Cadmium 0
Sulfur 1637

Phosphorus 623
Zinc 771

Oxidation 28%
Nitration 26%
Sulfation 35%

Soot 0
Glycol 0
Water 0
Fuel 2%


Viscosity at 100c 9.3
Viscosity at 40c 51.3
Viscosity Index 165


I put in Mobil 1 5w30 again and another AC Delco PF64 filter. Hopefully on the next oil change I will be able to find the new Mobil 1 0w40 ESP! I will probably do the second oil change the end of this summer/early fall.

As you know, GM calls for a 500 mile oil change on the dry sump Corvettes and mine is the wet sump but I still decided to do mine early. As you can see it has a high amount of silicon (from the new gaskets and assembly lube) and a little bit of fuel (I'm sure the engine got started and shut off cold a few times before it arrived at the dealer, and had probably a lot of idling too) That fuel caused the oil to thin out right to the point where it could technically be classified as a 5w20, so I'm glad I changed it early. My OLM was still at 80%.

Iron is high, copper is high, but both of those will settle down once the engine breaks in.

Maxpowers

Pat. When you sent this in for analysis did they give you any sort of narrative to interpret the results. Or did you figure that out on your own?

Patman

Wearcheck really doesn't say too much in terms of interpretation for the results they give. They assume their users have the ability to interpret their own results. That being said, when I got my last oil analysis on my Honda, the fuel contamination was very high and the first thing they wrote on the report was to check the fuel injection system. That's kind of vague though, but I know from experience that this means I have a leaky injector or two on that car (which I have been able to fix in the past just by running a few doses of Gumout Regane or Techron)

After 16 years of doing oil analysis, I am pretty good at interpreting my own results but I always post my results on bobistheoilguy.com and there are plenty of people on there who can help me out if something stumps me.

Patman

After getting these results it also clicked off a light bulb in my head as to another possible reason why GM is now recommending the new 0w40 for these engines. Two words: fuel dilution. Direct injection engines by nature have a higher level of fuel dilution in the oil, which in turn lowers the viscosity. As I mentioned, my oil turned into a 5w20 in a very short period of time. I bet GM has been paying attention to this type of thing in their long term testing, and to counter that, they want the LT1 to have a thicker oil so that when a little bit of fuel gets into the oil it will not end up turning into a 20 weight.

rmorin1249

Great post, Patman. Very interesting data.

vxplt

lakemg

1217 ppm Calcium? Someone must have dumped a little milk in the oil...

SLOWRYDE

190C (374F) would certainly do that and much more

Patman

I know you meant 190F I don't do short trips in my Corvette, so I always get the oil above 190 for a good length of time. I like how quickly my oil gets up to that temperature actually, it gets there a lot quicker than my C6 did. On a cool morning it would take the entire drive to work for my C6 to get the oil temp to 190. In my C7 it gets there at the halfway point of that same trip.

Gonzo

Thanks for posting your results !!

vxplt

Maxie2U

IMO, all that info was completely meaningless.

When I had oil analysis done on my airplane the people I used not only provided the same type of information they also provided a complete perimeter breakdown with conclusions like; based on the high content of nitrided steel a piston ring or rings may be experiencing a higher than normal wear pattern(s). If this trends continues either have a compression test. Done or have the cylinders inspected or bore scoped.

walleyejack

is that because you don t know how to figure it out on your own and need someone to splain it to you ?

Avanti

" I bet GM has been paying attention to this type of thing in their long term testing, and to counter that, they want the LT1 to have a thicker oil so that when a little bit of fuel gets into the oil it will not end up turning into a 20 weight."

And, it took GM how long to figure this out???

Maxie2U

So tell us genius what does all this mean or do you someone to “splain” it to you. And be specific.

ron 48
Lead 2.7
Aluminum 3.5
Copper 36
Chromium 0.8
Nickel 0
Titanium 0
Tin 0.8
Silver 0
Vanadium 0

Silicon 124
Potassium 6.2
Sodium 4.5

Moly 151
Boron 82
Barium 0.3
Calcium 1217
Magnesium 446
Manganese 2.1
Antimony 1.4
Lithium 0.3
Beryllium 0
Cadmium 0
Sulfur 1637

Phosphorus 623
Zinc 771

Oxidation 28%
Nitration 26%
Sulfation 35%

Soot 0
Glycol 0
Water 0
Fuel 2%

And the difference between you and I is when I pay an expert for an analysis I leave it up to the expert to explain it.

Patman

Not to me it isn't. Once an engine is broken in and the wear metals settle to a consistent level, and you get a bunch of reports in a row, you can watch the trends and see if something goes awry. It's also good to see how the viscosity is holding up as well as checking for things such as fuel and glycol.

Foosh

Pat, I found the results very interesting, especially your observation about DI and fuel dilution of viscosity. The silicon content numbers were enlightening as well, which is consistent w/ GM's guidance to do dry sump changes at 500 miles. Thanks.

Patman

I'm surprised GM doesn't extend the 500 mile recommendation to the wet sump cars as well. With the high silicon, fuel and iron content I'm already seeing in the oil at this early stage, it's already at the point where it really should be drained out. I would hate to see what this report would have looked like if I had gone 5 or 6000 miles (which is probably the mileage where it would have hit zero on the oil life monitor if I kept going)

Foosh

Agree. Based upon your results, I think all wet sump cars should have the oil changed @ 2K miles max. The dry sump 500-mile recommendation was because of engine silicon seal curing degrading the anti-foaming agents causing occasional oil foaming through dry sump vent lines into the air intake. However, it looks like other things are going on as well.

I'll also be going to 0W-40 hopefully no later than the 50% point after my 500-mile change. I'm already at 1K miles in a month after delivery, and changed the oil @ 590 miles. After the first 0W-40 change, I'll just follow the OLM.

4thC4at60

I guess I'm lucky... no engine failures in more than 700,000 miles in my last six Vettes.

My last C4 had 186K on the clock when I sold it. It's now got more than 250K on it... still runs fine....

My C6 was mine for 127,000 miles. The sales manager where I traded it bought it for his mother who now has 227,000 on it....

I'm always blown away with the minutia on this forum that many consider important.