Why do companies back spec oil?

[aquariuscsm]

For instance,my generation 8 Accord. The first year for the Generation 8 was 2008 and it spec'd 5W20. Then in 2011 they changed it to 0W20. What is the actual reasoning for this? Does it take years and research to "tailor" engines to the absolute best oil for them? Is it the oh so dreaded (drum roll please) CAFE credits? I'v always wondered what the actual rationale behind this is.

If this has been already discussed and concluded here,my apologies in advance.

 

[Astro14]

Simplification of dealer inventory and service.

 

[BMWTurboDzl]

Basically newer formulations perform just as well, they're readily available, CAFE is icing.

 

[demarpaint]

Originally Posted by Astro14
Simplification of dealer inventory and service.

And/or to possibly to start pushing a new grade to increase demand?

 

[Pinoak]

good question.

 

[Snagglefoot]

To keep this from being a thick thin discussion how about if we discuss this as a 0x vs 5x because the same questions apply to a 0w40 vs a 5w40.

Even though the viscosity difference between 0 and 5 doesn't get super noticeable until -35 C , I believe we saw some viscosity differences at milder temps for start-up conditions. Start up wear is real and viscosities at 20 C are much larger compared to 100 C. Recall the viscosity chart from a few weeks ago. For start up, getting oil into the galleys fast is a good thing. Every bit helps. And yes I know there is a residual oil film on the bearings and cylinder walls, but sooner you get pressurized oil in there, the better. It's really important to realize that 0 weight oil at 70 F has a higher kinematic viscosity than a 40 weight oil at 212 F. This is just at start up conditions and within minutes the kinematic viscosity drops drastically as the engine warms.

 

[OVERKILL]

Originally Posted by aquariuscsm
For instance,my generation 8 Accord. The first year for the Generation 8 was 2008 and it spec'd 5W20. Then in 2011 they changed it to 0W20. What is the actual reasoning for this? Does it take years and research to "tailor" engines to the absolute best oil for them? Is it the oh so dreaded (drum roll please) CAFE credits? I'v always wondered what the actual rationale behind this is.

If this has been already discussed and concluded here,my apologies in advance.


In this particular instance I wouldn't consider it a "back spec" because both oils are the same grade. It sounds like they just started using 0w-20 instead of 5w-20, which would provide better low-temp performance and subsequently made it the standard grade. This would result in it replacing 5w-20 in applications that originally spec'd it.

When I think of back-spec'ing, I think more of examples like where Ford switched from 5w-30 to 5w-20, going down a grade, which would involve testing and validation that this was appropriate.

 

[RooflessVW]

Originally Posted by Astro14
Simplification of dealer inventory and service.

Exactly. And also to clear up any confusion - my owner's manual says I can run anything from 5W-40 to 20W-50 but Porsche came out and said "M1 0W-40 for everything" and solved inventory and quality issues in one fell swoop.

 

[Hall]

Originally Posted by aquariuscsm
Does it take years and research to "tailor" engines to the absolute best oil for them?
I don't think many automakers actually come out with entirely new engine designs very often. Our son drives my old '99 Accord w/4-cylinder and while it's a 2.3L, I'll bet it's the same basic design as your '12 2.4L engine or close enough that the oil viscosity makes no difference. And while won't go back to '99, for example, to back-spec oil like they did with yours, I'll bet if we took it to a Honda dealer for an oil change, they'd put 0W-20 in it.

 

[MoreCowbellAz]

Add to that question the issue of back spec'ing an oil, and then dealers still installing the original recommended grade. For example, the 2.4L 2azfe engine in my '07 Toyota Rav4 was originally spec'd for 5w30, and around '06 or '07 was spec'd for 0w20 or 5w20, not a word about using a 30 in the manual. That's with no engine design changes. Then whenever I've had a dealer oil change (rare), it's always states they put in 5w30. Always. So not sure what Toyota's thinking is, other than it just doesn't matter in reality.

 

[JohnnyJohnson]

Originally Posted by MoreCowbellAz
Add to that question the issue of back spec'ing an oil, and then dealers still installing the original recommended grade. For example, the 2.4L 2azfe engine in my '07 Toyota Rav4 was originally spec'd for 5w30, and around '06 or '07 was spec'd for 0w20 or 5w20, not a word about using a 30 in the manual. That's with no engine design changes. Then whenever I've had a dealer oil change (rare), it's always states they put in 5w30. Always. So not sure what Toyota's thinking is, other than it just doesn't matter in reality.



The thinking they fooled the people in the CAFE program.

 

[y_p_w]

Originally Posted by hallstevenson
Originally Posted by aquariuscsm
Does it take years and research to "tailor" engines to the absolute best oil for them?
I don't think many automakers actually come out with entirely new engine designs very often. Our son drives my old '99 Accord w/4-cylinder and while it's a 2.3L, I'll bet it's the same basic design as your '12 2.4L engine or close enough that the oil viscosity makes no difference. And while won't go back to '99, for example, to back-spec oil like they did with yours, I'll bet if we took it to a Honda dealer for an oil change, they'd put 0W-20 in it.

I don't think they would do that, if only because many customers would complain about the price. I'm pretty sure most Honda dealer service departments still stock 5W-20 since it was still the standard until a few years ago.

 

[PimTac]

There may be some unknown improvements or updates to engines that are not disclosed and only enthusiasts may know about. Automakers are constantly changing products and designs along the way.

For example , the Mazda SkyActiv 2.5 got redesigned pistons and newly designed oil control rings for 2017. These were tweaks from the original design as they saw things that could be improved on. Continuous Quality Improvement (CQI) is what it's known as.

 

[ka9mnx]

Pistons, rings, bearings, liner coatings, oil pumps and oiling systems have been heavily researched to reduce drag and friction and to properly accommodate the new thinner oils.

 

[Hall]

Originally Posted by y_p_w
I don't think they would do that, if only because many customers would complain about the price. I'm pretty sure most Honda dealer service departments still stock 5W-20 since it was still the standard until a few years ago.

I forgot that 0W-20 is only available as a synthetic (at least I think so) so on the cost aspect, yeah, you might be right. Then again, the point of Honda back-spec'ing the oil was partly so that their dealers could stock/use fewer oils so they could make up the higher price of synthetic with bulk purchasing.

 

[y_p_w]

Originally Posted by hallstevenson
Originally Posted by y_p_w
I don't think they would do that, if only because many customers would complain about the price. I'm pretty sure most Honda dealer service departments still stock 5W-20 since it was still the standard until a few years ago.

I forgot that 0W-20 is only available as a synthetic (at least I think so) so on the cost aspect, yeah, you might be right. Then again, the point of Honda back-spec'ing the oil was partly so that their dealers could stock/use fewer oils so they could make up the higher price of synthetic with bulk purchasing.

The way they've back spec'ed them is a little bit funky though. Frankly I don't see why any vehicle where 5W-20 is back spec'ed can't also have 0W-20 listed, but they don't do that. I even remember back when 5W-20 was a fairly new recommendation, some people were thinking of using Honda's special 0W-20 (for the hybrid Insight) because it was known to be a "synthetic oil" and because it had Honda's specific approvals that were needed for 5W-20 applications.

Still - they started with the XW-20 oils 18 years ago. Although I suppose there's discussion about the meaning of "synthetic", but the API SN Plus standard is pretty high and even most 5W-20s are robust. I even wonder if it would have made a difference with the notorious Toyota or Honda sludge monsters if API SN Plus were somehow transported back in time.

 

[Hall]

Originally Posted by y_p_w
The way they've back spec'ed them is a little bit funky though. Frankly I don't see why any vehicle where 5W-20 is back spec'ed can't also have 0W-20 listed, but they don't do that.

It looks like they're pretty consistent. In almost all cases where 5W-20 was the original spec, they are showing 0W-20 as acceptable now. The Civic GX is one exception. I'm not sure what's unique or different about this model. The 2001-2002 Accord is another exception. There, the engine is the same from '99-'02 too but it looks like they were transitioning from 5W-30 to 5W-20. One thought was they only went back so far per model and maybe that's still the case.