Oil Viscosity? What's Best

[Cobranut]

Jerry,

Thanks for the info. You may be correct about the phos limit applying only to the lighter weight oils.

I went to Mobil's website and they make a definate distinction for the 15w50 weight. They refer to it as their "Performance Driving Formula" and state that it "Contains additional wear protection required for racing type engines."
I suspect (and hope) that this may be the higher phos. content.


Steve,

Actually, the PSD holds 15 quarts, and usually needs 1 quart added at about 3-4K miles when used for heavy towing. (Which is what we bought it for anyway). Plus, the filter is about $9.00.
So an oil change with Delvac-1 would be over $90.00, versus $33.00 using Rotella.

Later,