[Shop-talk] Oil grade selection

[Mullen, Tim]

Chip Mautz wrote:
>
> On another note - be aware, there is a new mobil 1 formula, which
> may not protect like the mobil 1 of old.

I don't know of anything specific to Mobil 1, but the new API "SM" rated
oils (the current standard) have a reduced amount of one of the
anti-wear additives compared to the previous API "SL" standard.
Apparently there is concern that when the engine wears and start to burn
oil, the additive will cause damage to the catalytic converter.  The
additive is one intended to protect against high sliding forces, and the
thinking is that since more (most?) modern engines tend to have roller
in the cam followers/lifters then need for the "Sliding ware additive"
is less.

One way to get the old additive package is to get oil intended for
diesels (such as Mobil 1 Turbo Diesel oil or others) which still tend to
rated as "SL" instead of "SM" oils.  Regular Mobil 1 oils (and probably
most other brands) have been "upgraded" to the new "SM" standard.

Tim Mullen

Chantilly, VA