5W 20 SL vs. SM

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Dec 5, 2005
Herndon, Virginia
Regarding the chemistry, in real-world terms, practical effects, and science, what's the difference (if there IS a difference in "real-world" terms) between, say, Havoline SL 5W20 API SL and Havoline 5W20 API SM? I have no particular love for Havoline, other than the fact that it's always chatted up here and the fact that I bought 2 cases of the stuff on sale owing to M-1's RIDICULOUS price increases of late, and AA's recent sale price of 1.58/qt. Ok, ok, I like the Moly content and high flash point of the Havoline. It should easily go 5000-7500 OCI, right?

My roller-skate 2005 Hyundai Accent GT 1.6 DOCH (10K total miles) specs 5W20 SL (no brand mentioned) with an option of 5W30 if 5w20 isn't "available". Of course, SL-rated 5W20 simply is NOT available. I bought a small 3 5-Quart jug stash of SL-rated M1 5W30 from Wally-World awhile back, but the scuttlebutt and what-not is that 5W20 is the best deal mileage-wise.

So, what's lacking in SL vs. SM owing to EPA, manufacturer's specs, and the general cheapening of all things automotive? And, if I run the SM-rated oil, what's the additive pack (regarding VSOT 9big-time moly-add) and SLOB CD-2 big-time ZDDP-add), that I should put into the oil to bring the sub-standard (by all accounts) SM back to SL?

Does ANY of it matter? Or am I just a knucklehead for even considering these issues (I suspect i'm a knucklehead
, but not any more than the rest of you!)?
It doesn't matter whether you use SL or SM rated oil as long as you do realistic OCI's.

I wouldn't even bother with the VSOT or SLOB.
"Harder"? Meaning, just guessing, that the base oil in the SM grades being better, even with a reduced add-pack (to protect cats), stood up to the tests better than SL with greater adds from the refiner that built them?

Not arguing, I'm just curious as regards the near-universal desire to add VSOT/CD-2 SLOB to gain Moly and ZDDP in SM-rated oil. I realize the non-critical nature of my roller-skate Hyundai, but it's all simple curiosity.

Tinkering, as it were..

...near-universal desire to add VSOT/CD-2 SLOB to gain Moly and ZDDP in SM-rated oil.

Some cannot bring themselves to run "naked" oil. A certain segment of the Bitog membership feels compelled to add something, - anything - to their crankcase oil!

If you are running an older engine design with sliding friction components, ZDDP levels in SM oils may be an issue for concern.

But reports in the UOA forum for a variety of vehicles have not shown any increase in wear metals with SM oils.

SM oils must pass the Sequence IIIG test, which is 100 hrs @ 300F vs. the previous IIIF test, 80 hrs @ 300F. And this test sequence is run on the same GM 3.8L V6 design, so plenty of accumulated wear data that woiuld expose any abnormal wear trends with the GF-4/SM oils.

Go with a SH/SJ oil for your push mower, but pick the SM oil over the SL for your late model vehicle!
Nice! I'm a believer! Have been on the subject of 5W20 vs. 5W30. Nonetheless, ARE the VSOT or CD2 SLOB a useful add to gain Moly or ZDDP in new cars? Even if not "needed"? Or just, frankly, a waste? If there's no point, it's only increasing viscosity and adding "stuff", right? If it's of benefit to add these things, I'm all for it, I suppose.

Mine's a 2005 1.6 DOHC.

Thanks, Blue!
toocrazy2yoo, now that you're over your angst regarding SM motor oils, here's something else to chew on: Hyundai is among those engine builders who use no cylinder liners in their aluminum engines. Just thought you'd like to know...
Hmmm...thanks, Ray, I needed that..

Do tell, what are the ramifications of THAT?

I can live with it, and I was ok with the SM, too, just curious about the adds..

This thing has a NYLON valve/cam cover, what ELSE could they have cheapened, right?
Actually they have been using that Nylon stuff for quite some time and it is probably not Nylon but some other kind of resin. My experience with it in molding operations is that it is very strong heat resistent stuff. Have no fears.

P.S. Last I knew the 1.6 engine was good ol cast iron block.

There, see, Ray (as opposed to Sea Ray)?

I KNEW this was a "quality" steed!

Iron block! Now yer talkin!
I'm sure it's "adequate", but there's something about a plastic/resin/nylon valve cover, I dunno. Clearly, I dunno. About SO MANY things automotive!

This place challenges ALL the old assumptions..

Thanks Ken..
TooCrazy, Molakule has cautioned against excessive levels of ZDDP, as it can cause galling on shaft surfaces.

And the UOA's I've viewed with a 1/2 or full bottle of VSOT in the crankcase have only been, let's say, average.

To me, the friction modifier in VSOT, which isn't visible in UOA metallic analysis, probably provides as much or more benefit than the moly.

So a treat rate of 1-1 1/2 oz per quart for either VSOT or the CD-2 should provide some added insurance and not interfere with the performance of the existing add pack chemistry.
Ok, so I found my engine in there, AlphaII. If I read right (CI/AL), it's a cast iron bloc/aluminum head/aluminum cylinder liner? Others that list a third item I assume the cylinder liner is the same as the head material. Or would a cast iron block necessarily have iron cylinders to match?

Thanks, Ray, pretty cool chart. I don't know where you folks find this stuff, the stealer never has info like this to share..
"TooCrazy, Molakule has cautioned against excessive levels of ZDDP, as it can cause galling on shaft surfaces."

What type of ZDDP? what C chain? what alcohol?
Do not think so,

lThere are lots of ZDDP types maybe 6-8 kinds I'd love to see data but know it is "proprietary"
I run up to 2,000ppm and have LOW wear numbers.


Makes one wonder which kind is in the CD2 SLOB.

"Are you a good witch, or a bad witch?"

I think I'm gonna get out of the additive vice, because as we all know, what were once vices, are now habits.

Anyone wanna buy 6 silver bottles of VSOT and 5 Hot-Pink SLOBS?

I'm gonna kick it cold-turkey.
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