Originally Posted By: turtlevette
quote from page 11 of this thread. Letter from Ford to their dealers:
Q. Why did we change to 5W-20? What was wrong with 10W-40, 10W-30 etc?
A: 10W-30 and 10W-40 are old technology. We introduced 5W-20 to take advantage of new technology in the industry to provide improved fuel economy, low emissions, and better engine protection.
Maybe I'm reading between the lines here. But I think they're saying 10W is old man's oil.
Today's conventional 10W40, not as terrible as in the 1970s, but still much more problematic than today's conventional 5W30. If given appropriate applications, 30 and 40 and 15W40 (preferably without Mg detergents
) and 20W50 preferable to 10W40. Of course BITOGers know this, so they run the full synthetic 0W40s and 5W40s.
Quote:
http://www.amsoil.com/news/2014_January_the_trend_toward_lower-viscosity_motor_oils.pdf
How Low Can Viscosity Go?
The trend toward lower-viscosity oils
began decades ago as a way to improve
cold-weather performance and fuel
economy. Given today’s strict fuel economy
requirements, OEMs will continue to
recommend lower-viscosity oils.
1911
SAE J300 Engine Oil Viscosity
Classification Standard is published,
defining five monograde oil viscosities.
1952
Winter-grade (“W”) viscosities are added
to the SAE J300 Standard.
1970s
Many OEMs recommend 10W-40 due
to its performance throughout a broad
temperature range.
1980s
10W-30 becomes popular due to its fuel
economy benefits.
1990s
5W-30 overtakes 10W-30 due to its
increased fuel economy.
2000s
Low-viscosity oils such as 5W-20 and
0W-XX are introduced to further increase
fuel economy.
2013
SAE 16W is added to the SAE J300
standard, clearing the way for 0W-16 oils.
Quote:
http://www.rockauto.com/Newsletter/archives/9-19-13.html
Like with old engines, oil in newer engines still needs to lubricate the moving parts while not leaking into the combustion chambers. However, oil now often has other important duties. Engine oil may have to act as a hydraulic fluid in engines with variable valve timing, multi-displacement or other systems with small orifices and pressure sensitive parts.
Engine oil also may have increased cooling duties. The four cylinder in my wife’s 1993 Ford Tempo takes five quarts (4.73 liters) of 10W-30 just like the V8 in our 1992 Dodge van does. Newer engines may need seven quarts, ten quarts or whatever volume is needed to keep the engine, turbocharger and other systems lubricated, pressurized and cool. An oil pump designed to pump seven quarts of relatively light weight synthetic oil is probably not going to be happy trying to move seven quarts of old 30 weight racing oil. Some oil passages or the oil filter might be left dry.
I wonder why 10W-30 is still sold at nearly every convenience store? I do not complain because it is what I need for my old cars, but how many drug store shoppers still have cars over 20 years old in their fleets? 5W-30 was already becoming the new normal in the early 1990s. Maybe significant numbers of people are putting 10W-30 in newer cars when they should not. Mixing weights of oils (for example 10W-30 mixed with 10W-40) always risked clogging the oil passages with goo. I imagine that really bad goo might happen if 10W-30 is mixed with 0W-20.
GF-4 and GF-5 10W30 conventionals and syn blends and Group III synthetics on the newer vehicles, it seems to me, could be used as a sort of high mileage motor oil. In my view 10W30 (the Energy/Resource Conserving kind) continues to most reasonably address both the needs for fuel economy (to minimize the fluid drag on the moving engine parts, and for easier cold weather starting) and the needs for protection under high load operation (for extended OCI).
As for Hondas and Toyotas with (0W20 on the oil cap) and as for Ford V8 modulars with very long timing chains (5W20 on the oil cap), and probably for others run by very sensitive variable valve timing systems, I must strongly suppose, given the above information, that the Group III synthetics PP 5W30 Dexos1 (ACEA A1/B1) and QSUD 5W30 Dexos1 (ACEA A5-02) and others similar to them in performance like PP PurePlus Dexos1 (ACEA A1/B1, A5/B5) (and preferably not containing PAO and very possibly no esters either, and not using extra additive products, for the earliest part of a vehicle's life, so a Motorcraft/Honda Syn Blend is acceptable too as I think on this matter) most reasonably address both the needs for fuel economy and the needs for protection under high load operation. The earlier part of a vehicle's life is not clear cut, as it could be the first 50K miles, or somewhere between 50K and 100K, could even be after 150K, depending on various factors within and without the control of the owner.
According to this line of reasoning and supposition concerning the latest vehicles, certain mainstream 5W30s could be called "the new 10W30"!
And then you've got the GDI engined vehicles.
I guess one must be a BITOG student to buy and reasonably operate these new ICE cars and trucks today. Or become mechanics themselves. And folks join because they perceive that the dealers by themselves are not able to supply the relevant education. Pretty amazing, the sophistications underneath the shiny new paint and behind the nonstop advertising, as if they were plug and play products.
