Originally Posted By: Hokiefyd
Originally Posted By: Phishin
How do we know what form of Moly is in PYB vs. PUP?
We don't. That's why it's speculation.
This was fairly widely discussed a year or two ago when we saw the molybdenum treatment rate decline by orders of magnitude in some oils (
notably some of the Japanese OEM oils).
From ConocoPhillips...
http://www.ocsoil.fi/upload/News on Lubes/ILSAC-GF-5.pdf
The TEOST 33C bench test evaluates an engine oil’s tendency to form high-temperature
deposits. This test was originally developed and included in GF-2 to evaluate turbocharger
deposits. It was not part of GF-3 or GF-4, but is back in GF-5 in anticipation of greater use of
turbochargers. Turbochargers allow the automakers to use smaller displacement, more fuel-
efficient engines while still maintaining high power output. Deposit buildup in the turbocharger
bearing areas can lead to loss of engine performance, turbocharger failure and possibly engine
failure. In GF-2, the maximum limit for deposits was 60 mg. For GF-5, the maximum limit is 30
mg
(except there is no limit for SAE 0W-20 oils because some Japanese OEMs recommend
SAE 0W-20 oils with high molybdenum content which will not pass this test).