Originally Posted by rayk

Appears DEXOS1 that GM markets is synthetic blend. That's why it's cheaper.

http://www.smittysinc.net/SiteFlyers...exos1Flyer.pdf

I did find on the GM dealer network where DEXOS was costing them about 1800 for a 55 gallon drum. They mark it
up to 3100.

Originally Posted by realoldguy

Hmmmmmmmm......55 gallons is 220 quarts (I hope). At $3100 for 220 quarts that works out to just about $14/quart. Is that what GM dealers charge for oil? I am glad that I change oil myself and use Mobil 1 from WalMart.

Originally Posted by cclive

Dexos is not an oil, it is a set of standards. Many oils meet the Dexos standard. These will have the logo right on the bottle.

If the service tech is confused, one remedy would be to buy the oil at Walmart and bring it with the car for him to use. He can then match up the logo on the oil cap with the logo on the bottle.

Originally Posted by Travelor

The question was WHY?

I think someone hit it on the head - Profit. here is an interesting read:
http://www.tireindustry.org/dexos.asp

A quick check on Google found the DEXOS oil retails for $593/55 gallon drum as compared to Mobil 1 at approx $1700/barrel.

And no the Tech was not confused as his dealership has a bulk oil labeled DEXOS on the overhead oil supply and his dealership sells it as "DEXOS" to its customers, not XYZ oil that meets DEXOS standards.

I think we really have beat this one to death now.

George

Originally Posted by cclive

So I guess GM doesn't make Dexos oil at the AC Delco refinery in Michigan...


Mobil One has the Dexos logo right on the front of the bottle, so no service tech should be confused.

Originally Posted by dkvetteguy

Why ? Its an engine LS3 not more advanced than the LS2 The LS2 was in the tahoe SS also and others [CTSV -old one] Oil that is a month old is no worse than brand new stuff! Thats totally rediculous!

Originally Posted by dkvetteguy

Yah ! Because due to the poor sales of our cars GM knows the oil will be sitting in the vettes for up to 2-3 years before its changed!

Originally Posted by Travelor

Why did GM change recommended oil for Corvette's from Mobil 1 to Dexos?

Originally Posted by Subdriver

There are aftermarket alternatives to dexos1:
AMSOIL Signature Series 5w30

Originally Posted by need-for-speed

So, is Dexos a blend of synthetic / dinosaur oil ?

Originally Posted by LDB

All of the oils that are constantly discussed on the forum are varying blends of group 2, group 3, and group 4 base oils. Groups 2 and 4 are very easy to define. Group 2 is conventional “dino” oil, simply refined from crude oil. Group 4 is made up of various synthetic, manufactured polymers, mostly poly alpha olefins or PAO. Almost all experts would agree that group 2 are lowest quality of the base oil groups. Group 3 are the toughest to define, both in terms of origin and quality. They start out as group 2, but are then subjected to extremely severe processing called hydrocracking, where hydrogen is added over a catalyst at pressures of about 2500 psi and temperatures of about 700F. During that process, most of the lower quality ring compounds, and essentially all of the heteroatoms like sulfur and nitrogen are removed. Most experts agree that group 3 oils are considerably closer to group 4 than to group 2 in quality, but most would also agree that they are not quite as good as group 4. But in terms of cost to manufacture, group 3 is closer to group 2 than to group 4. Knowing that, you can guess where this is headed.

Mobil 1 was originally group 4. Castrol started marketing a group 3 oil as being fully synthetic, on the basis that the severe hydrocracking of group 3 scrambled the hydrocarbons enough to call them synthetic in the sense that the resulting molecules are not naturally occurring. Mobil sued them, but lost. So now, in the USA, both group 3 and 4 oils can be advertised as being fully synthetic. As a result, even if the oil is advertised as fully synthetic, unless they specifically say it is group 4 (Mobil 1 does not), you do not know how much, if any group 4 oil it contains. Since they lost the lawsuit, Mobil refuses to answer the group 3 vs 4 question, so it is pretty clear that rather than label Mobil 1 as group 4 and continue making it as they originally did, they are using at least some group 3 base in Mobil 1. Just like any other oil that is labeled fully synthetic, but not labeled group 4, you cannot rule out the possibility that it is 100% group 3.

Before you start screaming that Mobil 1 is no longer any good, remember that it still meets 4718M spec. That spec doesn’t say anything about group 3, group 4, or synthetic, it simply sets standards for thermal stability and wear in engine testing. Those standards are so stringent that it is essentially impossible for a group 2 oil to meet. But now you ask the question, is a group 4 oil that meets 4718M better than a group 3 oil that meets 4718M? Beats the heck out of me. I’m sure both GM and Mobil have run such tests on original versus current Mobil 1, so they know that answer. But they aren’t talking. My guess would be that original Mobil 1 which was group 4 probably tests a smidgen better than current Mobil 1 which is a group 3-4 blend, but the difference is hardly enough to notice. They are both excellent oils, and had Mobil not gone to some group 3 in Mobil 1, you can be sure its price would have risen.

As far as the consumer, once the courts and lawyers put their ugly stamp on things by making the therm fully synthetic cover both group 3 and 4, it would be nice if the companies had responded by voluntarily labeling by group number like most do in Europe. Unfortunately, that hasn’t happened here yet, so as of now, unless the oil is one of the few that are labeled group 4, you have no way of knowing whether your synthetic is group 3 or 4. But you can hang your hat on the fact that both groups are excellent oils, so I really don’t think it’s worth too much worry.

Originally Posted by Hairbag

Dexos is the 2-year old oil performance spec for GM vehicles. AC Delco Dexos is a syn blend. Both Mobil 1 & AC Delco Dexos are available to GM dealers in qts, 55 gallon drums or bulk as needed by the dealer. AC Delco Dexos spec oil is the minimum performance oil standard for your 2011-2012 GM vehicle including your vette. Mobil 1 5w30 does meet the Dexos performance standards and would be a step up oil performance over the AC delco Dexos product.

AC Delco Dexos---Good

Mobil 1 5W30------Better/Best

Originally Posted by jovette

All LS3 dry sump, LS7 and LS9 corvette engines were factory filled with Mobile 1. Currently, all C7 LT1 dry sump and LT4(Z06) corvette engines are factory filled with Moble 1. C7 Stingray LT1s are factory filled with Dexos standard synthetic blend oil. This information came from GM Factory Rep.

Originally Posted by Way2FastZ06

The LT4 is filled with Dexos and labled so on the new Z06. I know first hand. Wish i knew how to post pics here...

Originally Posted by Red Devil

If you do a little more research you will find that Mobil 1 is not true synthetic oil, I believe their only true syn oil is their 0W-40 weight. That being said, if you change your oil when or before indicated it's hard to find better oil for the money. I love the Redline of products but they are pricey.

Originally Posted by fnbrowning

No, far from it. Here's the straight dope from our local expert!