Quote:
Originally Posted by kawasaki00
I will run the 0 40 at work tomorrow, I have a really old bottle of TWS (4 years) I checked it before at like 1700 zinc. The new stuff is down to 900 to 1000
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1700 ppm in TWS has got to be an error of some kind, maybe contamination of some sort in the lab or in the sample handling. Mobil racing oils have 1700 ppm zddp and Mobil (on their web site) recommends it only for racing (and probably very short drains) and not for street use. I have a voa of TWS done in Jan 2009. It had 641/796 zddp, but was rated API SJ. That low a level of zddp would today qualify it as a low saps API SN fuel economy oil (good for your Tahoe). It must have had some ester in it, like castor oil, for antiwear, which wouldn't show up in a voa.
Back to Mobil 0w40: the buzz on BITOG is that it has recently been reformulated, as well, and is now a better oil - - it used to shear back rather quickly.
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