2005 MB E500 Mobil 1 0w-40 FS - oxidation
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Is it missing or am I just missing it in UOA. What were the miles?
TBN is 4.4.... so oxidation isn't from acidification.
"Oxidation stability is a chemical reaction that occurs with a combination of the lubricating oil and oxygen. The rate of oxidation is accelerated by high temperatures, water, acids and catalysts such as copper. ."
Do you by chance have an oil cooler that's made out of copper?
Iron is very low for 10k miles.
Someone here once said if TAN is high, then tin and copper track proportionally. So I doubt that your tan has crossed the TBN number.
"The rate of oxidation increases with time. The service life of a lubricant is also reduced with increases in temperature. Oxidation will lead to an increase in the oil's viscosity and deposits of varnish and sludge."
And yet the oil is at 12.2cst @ 100c... Where virgin is around 12.9cst.
"Oxidation stability is a chemical reaction that occurs with a combination of the lubricating oil and oxygen. The rate of oxidation is accelerated by high temperatures, water, acids and catalysts such as copper. ."
Do you by chance have an oil cooler that's made out of copper?
Iron is very low for 10k miles.
Someone here once said if TAN is high, then tin and copper track proportionally. So I doubt that your tan has crossed the TBN number.
"The rate of oxidation increases with time. The service life of a lubricant is also reduced with increases in temperature. Oxidation will lead to an increase in the oil's viscosity and deposits of varnish and sludge."
And yet the oil is at 12.2cst @ 100c... Where virgin is around 12.9cst.
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OVERKILL
$100 Site Donor 2021
Some oil chemistries will yield a naturally high oxidation value right out of the gate. Without virgin data on this lubricant, we really don't know if this is really "high" or just a false positive. I had an oxidation value of 39 with the older M1 0w-40 in my M5 after a run that was half as long as yours, FWIW.
4WD
$50 site donor 2024
Originally Posted By: amcguru
I'm thinking a botched UOA. I have been a Benz dealer tech since '00, and have NEVER seen a lubrication related failure or issue when following the specified 1yr/10-13k service intervals with oils that meet 229.5 spec.
Do you get the Formula M from the dealership?
I'm thinking a botched UOA. I have been a Benz dealer tech since '00, and have NEVER seen a lubrication related failure or issue when following the specified 1yr/10-13k service intervals with oils that meet 229.5 spec.
Do you get the Formula M from the dealership?
John_Dudes post is about the same thing I was thinking. Also: http://www.machinerylubrication.com/Read/14/lubricant-oxidation if you want some basics.
I'd take OVERKILL's answer as definitive, since he actually had half the miles and a higher Oxidation abs/cm. Oxidation is something not on a Blackstone report, since we usually just look at ending viscosity and TBN base number and flashpoint and then guess what happened.
You had almost 1% fuel dilution, and each percent is typically good for a 1 cSt drop in KV100. That takes it to 11.9 cSt. Then add in expected VII breakdown and guess it'd be another 1 cSt, which gets it down to 10.9 cSt. Now, oxidation almost certainly did occur to add the 1.3 cSt upward to the final 12.2 cSt.
This is all very normal, and your Fe wear rates look good, so no problem here.
Given this is an older Merc, consider doing one short-interval oil change of 2,000 miles to clean it out a little, then go right back to 10,000 miles changes.
I'd take OVERKILL's answer as definitive, since he actually had half the miles and a higher Oxidation abs/cm. Oxidation is something not on a Blackstone report, since we usually just look at ending viscosity and TBN base number and flashpoint and then guess what happened.
You had almost 1% fuel dilution, and each percent is typically good for a 1 cSt drop in KV100. That takes it to 11.9 cSt. Then add in expected VII breakdown and guess it'd be another 1 cSt, which gets it down to 10.9 cSt. Now, oxidation almost certainly did occur to add the 1.3 cSt upward to the final 12.2 cSt.
This is all very normal, and your Fe wear rates look good, so no problem here.
Given this is an older Merc, consider doing one short-interval oil change of 2,000 miles to clean it out a little, then go right back to 10,000 miles changes.
10k miles and only 11 ppm iron. Mibil 1 0w-40 is pretty impressive oil
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