10w-40 Gets A Bad Rap!

[brianl703]

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Originally posted by jbas: new Kia (with affiliate Hyundai the fastest growing car companies selling in America) with 3.5L V6 calls for, uh, 10W-40

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Doesn't it also call for API SG oil?

 

[jbas]

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Doesn't it also call for API SG oil?

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You're close: "API Service SH or above." The oil grade table is unlike anything I've seen before. Koreans' must like viscosity. Examples, approx.: 5W-30: -25 to 40 30wt: 40 to 120 10W-30: 0 to 90+ 10W-40: 0 to 120+ 20W-50: 20 to 120+ 5W-20ers: -25 to 0

 

[SteveS]

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Originally posted by Bror Jace: Yes, I'm pretty sure this subject has come up before, I think most of the bad rap 10W-40 gets is from early formulations using lousy, unstable viscosity index improvers which made a mess of many an engine decades ago. --- Bror Jace

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You're quite right, this anti-SAE 10W-40thing goes way back See, there's different kinds of VIIs. Basically a high molecular weight VII will have a greater viscosity index affect but will be less shear stable. So while you'd use less of a high molecular weight VII (more economical) it would lose grade in use. And that's what was causing problems with SAE 10W-40s, they'd start as an SAE 10W-40 but in service they'd soon be a 5W-20, and engine problems. Now a low molecular weight VII needs more VII to get the same viscosity affect, so more expensive. But a low molecular weight VII is more shear resistant so the SAE 10W-40 oil formulated with the low molecular weight VII would stay as a SAE 10W-40 through the entire oil change.

 

[haley10]

The 3K oil change wasn't a myth but, a good idea back when 10W-40 was a U.S. recommended grade. If you like 10W-40 dino, so be it, but disregard your manufacture's oci and do 3K. My flame suit is on now. I just do not see an application for dino 10-40. This does not apply to synthetics or GPIII psuedo-syns. I consider 10W-40 dino an obsolete product.

 

[TallPaul]

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Originally posted by haley10: If you like 10W-40 dino, so be it, but disregard your manufacture's oci and do 3K.

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No flame. Maybe my case is just the exception to the rule, but here is my 3000-mile UOA on Valvoline Maxlife 10w40. http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=001398 The oil performed well, stayed in grade, and was recommended by Blackstone to run to 4500 miles. Maxlife is basically a dino oil with a smidgen of synthetic (12-22%). If teh Maxlife performed that well, I expect Valvoline Durablend 10w40 would be even better. BTW, a typo says its a v-6, but really it is the straight six.

 

[Bror Jace]

haley10, I pretty much agreed with your post ... except I'd call 10W-40 dinos obsolescent and not quite obsolete ... yet. For any application you would be tempted to use a 10W-40 dino, a different weight would probably be a better choice (15W-40, etc ...). --- Bror Jace Edit: Yes TallPaul, I don't consider Max-Life a fair comparison as it is really a (real) synthetic blend. Not sure how a Group III/II 10W-40 blend would do. I'd like to see Pennzoil 10W40 pushed out to 4,000-5,000 miles to see how it holds up.

 

[haley10]

TallPaul it definitely worked. I take Blackstone's lab results, but I take their analysis and recommendations with a grain of salt. You ran a top brand, quality 10W-40 and didn't really stress it for 3k. What if someone goes and picks up a no name 10-40 and runs it for 7 or 8K like GM and Ford knows they would? Gotta remember what the average consumer is going to do. 10W-40 dino just ain't goint to stand the abuse from a lot of American consumers without problems. I have no problem with intelligent application, but I know why it is not a recommended grade anytmore.

 

[haley10]

TallPaul, comparing things like Maxlife and Castrol Syntec with the other stuff on the market , cheap ,is like comparing apples and oranges. Pushing a cheap 10W-40 will result in a sludge-o-matic.

 

[TallPaul]

You're right. Maxlife is not cheap oil (neither costwise nor qualitywise). I will be running some Citgo Superguard 10w40 over the next few OCIs, but this will be in conjunction with AutoRX treatments, so won't do much good for evaluating the oil (maybe the second rinse cycle which runs 3000 miles would be good to check how the viscosity holds up, but that will be in winter). And while I think the Citgo is straight dino, not sure it is exaxtly cheapo stuff. The note above about Chevron Supreme 10w40 sheering down is disturbing though. [ July 23, 2004, 03:00 PM: Message edited by: TallPaul ]

 

[Bror Jace]

"See, there's different kinds of VIIs. Basically a high molecular weight VII will have a greater viscosity index affect but will be less shear stable. So while you'd use less of a high molecular weight VII (more economical) it would lose grade in use. And that's what was causing problems with SAE 10W-40s, they'd start as an SAE 10W-40 but in service they'd soon be a 5W-20, and engine problems. Now a low molecular weight VII needs more VII to get the same viscosity affect, so more expensive. But a low molecular weight VII is more shear resistant so the SAE 10W-40 oil formulated with the low molecular weight VII would stay as a SAE 10W-40 through the entire oil change." I guess what somewhat disturbs me is that Chevron Supreme 5W-30 and 10W-30 will stay in grade throughout a modest OCI (about 4,500 miles) but the two 10W-40 UOAs I've seen showed this stuff (same brand) shearing down. Synthetic 10W-40s (real PAO/ester types) are an entirely different breed apart from their dino cousins. --- Bror Jace

 

[jbas]

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In short, if I want a 40 weight oil, I'll go with a 15W-40 dino or a 5W-40 synthetic for cold weather. Either would be better than 10W-40

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OK, but...the 15W-40 dino would be significantly thicker at start-up, than the 10W-40. Wouldn't that possibly translate to more wear? Less MPG? As for going with a 5W-40 synthetic, (presumably over a 10W-40 synthetic) that's fine, but the cost may be substantially more. Look at the Amsoil products. I think their new European 5W-40 costs 30-50% more than the AMO 10W-40, and supposedly offers a (potentially) significantly shorter OCI. There is all the same trade-offs we see in so many discussions. Finally, some others talk about only safely going 3K with the dangerous dino 10W-40. Well, what's wrong with that? Probably a conservative OCI, and an OCI of 4K is reasonably justifiable. But, many BITOG posters won't go further than that, whether a 5W-20, 5W-30, 10W-30, et al. So what's the difference for them?

 

[69 Riv GS]

Well, I see the myth continues. Let me start by saying that my '69 Mopar 383magnum runs on Pennzoil 10w-40, and has since day 1. And believe it not it hasn't turned into a molten lump of junk yet. It actually has 137,000 fairly aggressive miles, runs very strong, and is very clean inside. The original point of this thread was to highlight the fact that todays 10w-40(dino) is unjustly looked down upon. And, to prove it has the goods to "deliver". One or two examples of "shearing"(or anything) isn't strong evidence to refute this; and possible planned obsolescence is irrelevant. It's all about hard data + UOAs + visual parts inspection! I performed a crude comparision of viscosity "shear-down" for dino non HM 5w-30, 10w-30 & 10w-40 over 3-5K miles. Using the UOA section I randomly(except 10w-40; there were only 8) chose 8 samples. Before averaging I threw out the highest and lowest readings. Averages : 5w-30: cSt at 100*C 8.54 10w-30: cSt at 100*C 9.53 10w-40: cSt at 100*C 12.27 I then averaged the beginning viscosities(per PDS) of the test brands: 5w-30: 10.7 10w-30: 10.7 10w-40: 14.2 Which gives us the amount of original viscosity retained: 5w-30: 80% 10w-30:89% 10w-40:86% I did this to prove to myself, as well as others that 10w-40 can compete with 10w-30 in these terms!

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Would be interesting to see side by side tests of how the two hold up under stress. Which would suffer the most permanent viscosity collapse and which would produce the most sludge? Would the thicker Group I base hold up better than the thinner, Group II fortified oll or vice versa?

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Yes, this is interesting! I'd like to contrast the two on all aspects. The oil companies probably have some "old papers" that speak about this; wonder how we can lay our hands(or eyeballs) on them?

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I am not sure of this but I suspect you could be correct that the same basestock is used and the higher viscosity is achieved not only through viscosity modifiers, but by some kind of size exclusion process that would increase the amount of higher molecular weight component in the 10w-40. In general I think it safe to assume that your thermal properties, i.e. Noack and FP should improve with higher Mw. However, if the Mw blend isn't narrow enough and overly broad with a lot of viscosity modifiers, I think one could easily lose the added bonuses of the increase in high Mw components. I think these properties may be very dependent on the processes each company using to obtain their multi-grade oils. I will throw this out there and see the responses I get--It isn't necessarily the average molecular weight of the base stock oil, but the narrowness/breadth of the molecular weight that may have the biggest effect on your thermal stability.

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This makes alot of sense. So, this is essentially what each step up in group means; a narrowing of the MW range. Then, within each group there resides various weight(MW) oils that are blended to achieve the desired viscosity and characteristics. I'm catching on now! Chevron base oils TallPaul, Very nice UOA! I think Citgo should work great with AutoRX; because it's mostly group I. FWIW, their HM(UltraLife) has one superb additive pack. BTW, those 300cid last forever.

 

[TallPaul]

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Originally posted by haley10: I have no problem with intelligent application, but I know why it is not a recommended grade anytmore.

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You make a good point and the problem seems to be the grading system. If an API graded oil does not hold up, then the grading system seems to be at fault. Maybe there needs to be a better grading system, but until then we have UOAs and synthetic blends to help us ensure a better than grade oil. I dont see 10w40 as being obsolete, even considering 5w40 and 15w40 are available. Problem is, all else equal, a 5w40 requires a greater amount of viscosity index improver than the 10w40 and 15w40 is generally only available in heavy duty dual rated (gas/diesel) oil. I only know of one passenger car 15w40 and from the MSDS sheet info I posted, the 10w40 version of Durablend is much better. I will continue to run 10w40 in my 300 I6 at least. And it is clear to me that there are some very good 10w40s available, albeit not necessarily straight dino. Strange that, for an obsolete oil, Castrol just introduced a 10w40 in their Start Up oil. The auto manufacturers apparently want it to be obsolete, but the consumer and oil companies see it differently. Maybe the oil companies know better since they are not directly under the CAFE gun. [ July 24, 2004, 08:36 AM: Message edited by: TallPaul ]

 

[TallPaul]

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Originally posted by 69 Riv GS: Very nice UOA! I think Citgo should work great with AutoRX; because it's mostly group I. FWIW, their HM(UltraLife) has one superb additive pack. BTW, those 300cid last forever. [/QB]

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Thanks. I have had a couple trucks rust away from around the 300 I6 engines. BTW, I suspect (and had an oil company tech tell me) that 10w40 has a somewhat thicker base oil than 10w30. Makes sense to try to narrow the gap on the 10w40.

 

[69 Riv GS]

Old school 10w-40! really... ya don't say... (starts on 5th line)http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=000068#000008

 

[TallPaul]

Just bought two cases Durablend 10w40 today. Couldn't help myself when I saw the Pep Boys coupon for it at $1.99 per quart. Now I have 42 bottles of 10w40 in Citgo Supreme, Durablend, and Maxlife. I think the blend 10w40 can hold it's own against other grades. But if the bad rap is on pure dino 10w40, then we need also rip on 5w20 because, as far as I know, all these 5w20s are blends. And dino 5w30s are probably no better (if not much worse) than 10w40 dino. Apart from very cold climates, 10w40 may be the best grade going. Synthetic 5w40 is probably best in very cold climates. Fourty Weight Rules! Just kidding (I run 10w30 in both other vehicles).

 

[glxpassat]

Castrol's 10w-40 Syntec blend is ACEA A3 rated which means it has to be better than older 10w-40 formulations.

 

[TallPaul]

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Originally posted by glxpassat: Castrol's 10w-40 Syntec blend is ACEA A3 rated which means it has to be better than older 10w-40 formulations.

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Excellent point. And Durablend 10w40 is also ACEA A3.

 

[69 Riv GS]

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And Durablend 10w40 is also ACEA A3.

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10w-40 is the best grade of DuraBlend. The 5w-30 could only muster an ACEA A1 rating(not a slam on DuraBlend, but on 5w-30 in general) , and the 10w-30 has NO ACEA rating(un-popular weight in Europe?). I believe most consumers in Europe want an A3 rated oil, and good quality 10w-40s fit the bill. I can see me becoming more of an A3 man myself Oh yeah, I see TallPaul is single handily pulling 10w-40 out of it's sales slump! [ July 31, 2004, 03:01 AM: Message edited by: 69 Riv GS ]

 

[haley10]

I know, I've been tough on 10W-40's, but I'm wasn't referring to the A3 rated ones. I'm trying Syntec right now myself. A3/B3 Not cheap, but I'm comparing it to M1 10W-30 in my ride.