A few weeks ago I send an oil sample out, to be tested by Oil Analysis Inc. All the usual disclaimers apply, I don't, haven't, won't, can't etc... I just got the results back. I am quite happy to say that my truck (98 td wagon 12k) received a better report card that I ever did! Straight A's. My question to the list is this. Although they give you the parts per million of various metal concentrations. And give you a corresponding letter value. They do not tell you the cut off for each letter (e.g. Silicon 15 ppm = A). Is this closer to an A- or an A+? Most of the elements were in the single digits. The following were a little higher. Silicon 15. Iron 29. Some of the additives were much higher. Such as Calcium 2136. I realize this is considered an additive and would be found in higher levels than say Copper.

Can anyone on the list provide me with the scale of this evaluation?

Regards,
Bald Bill

Bald Bill,

After I sent an oil sample to Oil Analyzers, Inc., I also wondered what the numbers meant. The best they could provide me with was the "baseline sample" of the lubricant used (i.e., the properties contained in an unused oil sample). I don't know if you're using the same stuff in your truck as I am, but here goes:

For Amsoil 15W-40 synthetic engine oil, the baseline sample is as follows:

Viscosity at 100 degrees celcius is 15.2
TBN (Total Base Number) is 12.6
Boron - 32 ppm (parts per million)
Calcium - 4318 ppm
Phosphorus - 1255 ppm
Zinc - 1325 ppm

For Amsoil 80W-90 Synthitic Gear Lubricant, the baseline sample is as follows:

Viscosity at 100 degrees celcius is 15.2
TAN (Total Acid Number) is 3.3
Iron - 4 ppm
Copper - 1 ppm
Tin - 2 ppm
Boron - 162 ppm
Calcium - 15 ppm
Barium - 1 ppm
Phosphorus - 948 ppm
Zinc - 5 ppm
Titanium - 1 ppm

Bill King
96 N/A Wagon