Originally Posted By: d00df00d
Originally Posted By: dailydriver
But I went on their site, and the only "low ash" 15W-40 they list is the BioSyn Xtra HD Plus, which has a 3.7 HTHSV (which I take for granted is the ONE d00d was using), so I was WRONG, and it is essentially the same weight as M1 0W-40 as far as that is concerned (I did not look at MRVs).
RLI's data sheet says ">3.7" for HTHS, not 3.7 exactly. I'm pretty sure the real value is well above that.
MRVs are not comparable because they are indicated at different temps per the 15w/0w difference.
For me, the draw of RLI's 15w-40 Low Ash was twofold:
1. Low VII content. I hoped this would help control fuel dilution and oil consumption.
2. Low ash content. I hoped this would help control deposits and protect my emissions equipment (O2 sensors etc.).
Mobil 1 0w-40 has a higher number for sulfated ash (1.3% vs. 1.0% for the RLI) and presumably has more VII content.
Did you consider M1 10W-40 High Mileage? Less VII's although they don't list SA on the data sheet.
-Dennis