"Philip E. Barnes" wrote:
> use. The response was to use a "heavy-duty" oil intended for diesels. The
> reasoning was these oils have more additives for anti-oxidation and
> anti-corrosion than passenger car oils. The additives apparently have a
> detrimental effect on catalytic converters, so have been reduced or
> eliminated in "modern" oils. Made sense to me. Perhaps I'll go down to the
> local Kenworth dealer for my next oil change.
Curious... since every heavy-duty on-road diesel engine today is
equipped with a catalytic converter to meet emissions standards. I
suspect that oil formulations for diesel engines have changed, as well.
For what it's worth, we put Mobil Delvac 1200 in all engines, regardless
of make, except for natural gas engines which require a lower ash
content. Delvac 1200 is a 100% synthetic 15W-40, I believe. And we
recommend oil changes every 6K miles....
If you are looking for diesel engine oil with a pre-catalyst additive
package, look for an oil which only meets CC or CD specs. Those are
diesel standards which go back to the early `80s. They may simply not be
available, though.
Newest spec oils (up to CH-4 according to the Lubrizol site I use
frequently) probably resemble an additive package more like current
light automotive oils, so if you don't specify an older spec oil at that
Kenworth dealer, you may get a fancy, quite expensive version of
something you can buy at Pep Boys.
Have look at this site. It will probably explain a _great deal_ more
than the lubrication expert in Car & Driver:
http://www.lubrizol.com/referencelibrary/readyreference/6-OilClasses/Cclass.htm
It's fairly apparent from that page that classes CA through CE are now
obsolete. CF through CH-4 are likely oils suitable for use with
catalytic converters, since the ratings for each are referenced back to
properties of now-obsolete classes.
I highly recommend the Lubrizol site to everyone--there's a wealth of
information there, freely available, on anything and everything having
to do with lubrication.
Cheers, Phil.
|