I use 10w-40...sometimes. I use it in Euro cars. Looking at some oils today, Havoline 10w-40 is SL and some others are SM. GTX, MaxLife, Pennzoil, Durablend all are SM. Why would Havoline not be SM? Is it a matter of Havoline not wanting to meet additive level caps or do they just not care to reformulate a better product? I also wonder what is a 10w-40 SM anyway? Are the specs for 10w-40 lesser than 20s and 30s? Is there a real difference in performance of SM and SL 10w-40? How do the experts think a SM 10w-40 compares to A3 Synthetic 5w-40s in areas other than cold-cranking?
10w-40 SM
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I think the Havoline you were looking at was some older stock. You just about have to have a roller valvetrain to use SM. As far as 10W-40's go, I like the thinnest one, which would be Maxlife being 13.9 cst @ 100C. Amsoil 10W-40 is 15.7 cst @ 100C. In comparison, Amsoil 5W-40 is 13.7 cst @ 100C.
You state that view with such implied authority that I feel compelled to inquire which automaker(s) support that notion? I'm personally aware of at least one automaker that recommends API SM 5W-20 motor oil in its latest non-hydraulic, flat tappet, V6 offerings and backs its recommendation with a 10 yr./100,000 mile powertrain warranty on every car it sells in America.
Since a 10w40 would likely not meet the GF-4 fuel economy improvement requirements, you'll probably never find a SM/GF-4 10w40. However, if a 10w40 meets all the other test requirements, a 10w40 can be SM rated. Also, since it's a 10w40 and not one of the ILSAC viscosities (0-5w20, 0-5-10w30) there's no phosphorus limit imposed on it. Therefore, a bargain basement SM 10w40, has the potential to be better than a bargain basement SL 10w40, although it doesn't prevent anyone from producing a superior product and then decide to test and/or rate it a SL 10w40.
http://www.infineum.com/information/api-passenger-sm-2004.html (See Note 1)
http://www.infineum.com/information/api-passenger-sj-sl-2004.html
As far as comparing a SM 10w40 to a synthetic A3/B3 5w40, you'd have to be more specific on the make-up of the SM 10w40. If Amsoil or Redline, etc, made an SM 10w40, I'm sure it would be just as capable as any A3/B3 rated oil and would probably be dual rated as such.
[ August 18, 2006, 05:16 PM: Message edited by: 427Z06 ]
I feel "compelled" to ignore your post.
Ok, it was not old stock. Seems odd that Havoline would lag behind other brands with their conventional product. My comparison to A3 oils would be with SM conventional. Just wondering how close it would be to A3. Take DuraBlend 10w-40, I have a old box of SJ (maybe SL?) that carries A3 too. Would say, MC or GTX 10w-40 SM be nearly as good as a Euro A3 or DB 10w-40 for $2?
Here is a 3 page thread on 10w-40s.
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=007339#000002
A bit underrated, imo.
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=007339#000002
A bit underrated, imo.
I think it would depend on the OCI. A3/B3 oils are intended, and presumably built, for extended OCIs.
What I'm pointing out is that SJ Durablend 10w-40 meet A3 and it's a heck of a lot cheaper than 5w-40 synth. Could conventional SM 10w-40s be good cantidates for A3 if tested?
Durablend is also available in 15w40. The only PCMO 15w40 I have ever heard of.
I don't see why not. There's also the low SAP oils for diesels coming to market soon.
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