Mr.T

There are additives in engine oil that contain elements such as Boron and Molybdenum, but there's an presumption that new oil has zero PPM of wear metal elements like Fe (iron), Cr (chrome), Al (aluminum), Cu (copper), and Si (silicon). I haven't done it, but some people do a VOA (virgin oil analysis), and some of that is on the net. I've a vague memory of seeing a PPM here and there in VOA's that could be either test inaccuracy, the oil itself, or contamination.

I'm using Oil Analyzers, which uses Horizon, is affiliated with Amsoil, and has the VOA test data for all of Amsoil's product line. I don't bother to post elements like Boron since it's an additive, but they compare with the specific product VOA, and flag it if not within some tolerance. Had this happen when they revised a formulation, but not the part number, and I was one of the first to send in a UOA with the new additive formula.

A significant contaminant is what's left inside the engine after draining, which mixes with new oil. Presuming wear returns to previous, that may cause the next sample to be slightly higher than average.

Mr.T

Hard to believe it's over 100K miles already, and wear metals look extremely good. The air filter was probably the cause of the higher than average readings in the last sample. The indicator was silicon, which is the key element in dust. Washable air filters are nice, but they don't last forever. In this case, the filter lasted ~80K miles and was cleaned around 7 times. Back to OEM style air filters, and replacement rather than cleaning. IMHO there's too much potential for reduced filter efficiency after repeated cleaning. There's two ways to look at oil analysis, abnormally high readings and readings above average trends -- This was an example of the latter.

A 4K OCI is normal for many, but about half of what I normally run. Iron is looking particularly low and below average even on a per mile basis.

Oil: Amsoil AZF 0w-40
Filter: FRAM XG3600 (oversize, same as 2008 Jeep Liberty 3.7L)
OCI: 4000 miles
Oil added during OCI: NONE
Total miles: 100500

Aluminum (AL) 2 ppm
Iron (FE) 4 ppm
Copper (CU) 7 ppm
Lead (PB) 0 ppm
Tin (SN) 0 ppm
Chromium (CR) 0 ppm
Nickel 0 ppm
Cadmium 0 ppm
Silver 0 ppm
Vanadium 0 ppm
Silicon 10 ppm
Sodium 10 ppm
TBN 6.6

jedg

Always like to see your posts on this thread.

Rednroll

Now that you've reached 100K miles, it's time to break out an Excel spread sheet, and do a graph of OCI vs each PPM to see if you notice any trends starting to develop over time.

Mr.T

Good idea, PPM is the Y axis and the X axis is the sample number. Silicon (from dust) appears to trend up slightly, then take a big leap at sample 8, along with the wear metals. Hard to miss that correlation -- Air filters are critical for long term wear.


Latest fill is 0w-40 (AZF Amsoil) with a Fram XG3600 filter. Seems like the best qualities for extreme cold and hot climates. The Fram XG is a change this year, mostly I've used the Wix XP/NAPA Platinum. The Fram is a finer filter (>99% @ 20u) and looks well constructed inside.

Rednroll

Looks like a slight upward trend in Silicon and Iron. Have you concluded anything for the spike in sample 8 and the dive back down in sample 9?

Mr.T

Yep, I believe the spike in iron (and to a lesser extent aluminum and chromium) was from a washable air filter reaching it's end-of-life at the previous cleaning, and becoming less efficient. There's some inherent limit of how many times it can be cleaned. That lets a bit more dust into the engine, and some of that ends up in the oil as the element silicon in analysis. There's been no work on the engine that might introduce silicon, so dust is almost certainly the only source. After the spike, I changed the air filter back to a standard filter and will just replace it regularly (rather than cleaning it).

It's also possible there was more dusty conditions that OCI, but two or three times dustier isn't likely. Another thought is the gradual rise in silicon over the years prior to the spike is related to a loss of filter efficiency each time the filter was cleaned.

Rednroll

Thanks!! It sounds like I need to start changing my air filter more.

Seizer

Mr.T

Based on the last OCI, it's about 1 qt per 6K miles with 0w-40 (Amsoil AZF). No oil or residue on the throttle body, and the breather hose from the air cleaner to the valve cover is dry.

Suggest trying amsoil's engine flush, which may free up sticking piston rings. I used it last OCI on the Jeep, and have used it many times with several engines. My method is to idle with the flush longer the the directions say, and also put it in 4LO for a faster idle.