diitto

The local chevy dealer (Abel Chevrolet) that, in a separate post everyone who responded and I do mean everyone said these guys were the best place to take my new 2012 Corvette GS Convertible for service in Northern Ca (Bay Area). I am soon going to take my car to them to have an early, first oil change... I contacted them and they told me they supply both Mobil 1 and Amsoil. The manual tells me to ONLY use oils that are Dexos1 approved.... I know some of the Mobil 1 oils are Dexos1 approved but can anyone tell me whether any of the Amsoil blends (5w30) are Dexos1 approved??? And if so, is it MARKED on the container as Dexos1 approved??? thanks... bob...

calemasters

Here is the list of Dexos 1 approved (licensed) engine oils:

http://www.gmdexos.com/licensedbrand...sedbrands.html

diitto

Thanks for posting the link to the Dexos1 list... I had looked for that last night but missed finding one that I believed was current... What's interesting is that Amsoil doesn't appear anywhere on the list yet a Chevy dealer is offering to put it in a new Corvette... And it says right on the oil fill cap to use only Dexos1 approved oil... Hmmmm... Well, I guess as long as I stick with an approved version of Mobil 1 then I can't go wrong... I guess I'm a bit surprised a dealer, especially one that specializes in Corvette service would offer an oil that is not Dexos1 approved... Thanks for the list... much appreciated... bob...

KneeDragr

They are probably offering it because a lot of people like it and they know it wont hurt your car.

JCtx

Holy crap, I expected to see a few. Tons of oil companies I've never heard of. Good info. Mobil1 extended performance was added. Wonder which is better (Mobil1 or Mobil1 EP) if changed at 5K miles, due to time limit. In other words, which one has the more desirable additive package for the LS3. Thx.

Gearhead Jim

I don't think we can "know" that a non-approved oil won't hurt the car, until we know that the oil meets the Dexos specs.

Same thing with your warranty- GM would probably never raise the issue if you have an engine problem, but if they do; do you have the money to fight and win (or lose) in court?

There are so many Dexos1 approved oils from so many different makers, including plain old Mobil1, I just can't see using anything non-approved.

Gearhead Jim

Member LDB (retired chemical engineer from an oil company) gave his estimate that the Mobil1 EP would probably be of no benefit if you are changing at or before the OLI tells you to. But he has not seen what the "improved" additive package contains, so his comment is just an estimate.

KneeDragr

But the Dexos1 spec wasnt even out when the Corvette was designed, so your argument that Corvettes must run Dexos1 approved oils makes zero sense.

The Corvette was designed to run with oils using the GM4718M specification.

Dexos1 exceeds GM4718M, but that does not mean you need Dexos1.

Gearhead Jim

We are all assuming that the 2013 Corvettes, for example, have no internal changes that could make a Dexos1 oil important to use. I think that's highly likely to be correct, but it would take further research to be sure. Even the older Corvettes might receive a benefit from Dexos1 spec oil, but that would take tons of research that's probably beyond anyone except a chemical enginner/mechanical engineer combination.

On the Amoil site, the first three 5W-30 oils I just looked up all claim to meet the Dexos1 spec (I'm not sure about the European 5W-30). That's good news.

The bad news is that the Amsoil Dexos1 claim appears to be "just" a claim by Amsoil, they have not yet got onto the official Dexos list from GM. That's like what happened with some of the old 4718M oils; the oil maker claimed to meet the spec but they never got GM approval. There was the potential for an owner to get stuck between the two companies- GM claiming a problem was caused by non-spec oil, the oil company claiming their oil did meet the spec, GM saying "prove it and get certification", etc. The good news is that I never heard of that actually happening with 4718M, and hopefully it will never happen with Dexos1.

This is all made worse because GM appears to be using Dexos certification to make extra money, not just to certify good oil. That might increase the chances of GM getting sticky on warranty claims if the oil was not on their list.

But going back to post #5 from ELP JC and post #6 from me, there are so many Dexos1 oils (70+) from so many different suppliers (50+) that I just can't see taking even the smallest chance of a mechanical problem or a warranty problem, by using something not on the list.

ChevyDave

fyi... statement i found some time ago. it indicates GM's thought on pre-2011 cars (key word is encourages, not mandatory)...

General Motors is introducing dexos1™, a new global engine oil specification for gasoline and E85-fueled vehicles, in all 2011 model year Chevrolet, Buick, GMC and Cadillac vehicles. Basically, the company requires that every owner of these vehicles use an oil that is dexos1™ approved at every oil change. It also encourages owners of pre-2011 GM vehicles (except diesels) to use a dexos1™-approved oil as well, as the new specification offers several advantages over previously available motor oils, including improved levels of:
• Engine cleanliness
• Corrosion protection
• Sludge control
• Wear protection
• Aeration control
• Fuel economy
GM says these will result in improved engine life and performance.

JoesC5

The C5 and C6(through 2010) spec'd that the oil MUST meet GM4718M, The 2011 and 2012 owners manual spec'd that the oil MUST meet dexos1. Mobil1 meets both requirements. Actually, GM4718M exceeds dexos1. To meet GM4718M the oil had to be a "synthetic". A synthetic blend can meet dexos1. GM says that you can use dexos1 oil in place of the old GM4718M spec oil in the older Corvettes and it will not harm your warranty(or your engine).

AORoads

I did not know, nor have I read that years prior C6s (before 2010) can now use Dexos 1 vs. only 4718M.

I do agree, however, that it's a significant change (to me) that the "old" standard was for fully-synthetic oil (4718M) and the new standard as of 2010 models is Dexos1 which can be partially synthetic.

Can you/someone show where Dexos1 is now backward compatible? Thanks.

JoesC5

Sure, as easy as hitting a few keys.

http://www.gmdexos.com/aboutdexos.html

"dexos™ is recommended by GM for use in all its vehicles except those with Duramax diesel engines requiring the use of API CJ-4 engine oil. dexos™ is fully backward-compatible and can be used in older vehicles. It is specified in the owner's manual for all 2011 and later model years, with the exception of Europe where dexos™ is specified starting in model year 2010."

"•dexos1™ is designed for use with gasoline engines and replaces GM-LL-A-025, GM6094M and GM4718M"

Straight from the horses mouth....GM

JCtx

Interesting point. In the C6 case, the current LS3 started production in 2008. Nothing has changed on this engine to require a change of oil specification, especially going backwards, now allowing a synthetic blend oil. Therefore, I suspect a combination of EPA requirements (not good for the engine, but for the environment) and marketing/royalties. Not to mention GM is probably saving money by putting semi-synthetic oil in our Vettes, even though oil cap says 'Mobil1'. Who knows.

Bottom line is ALL of us know our engines would be absolutely fine with Amsoil or any other high-quality synthetic oil, but like JoesC5 said, it's just not worth the risk during warranty IMO. Not with so many great oils to choose from. Remember sometimes manufacturers blame stuff totally unrelated to the root cause of a problem, so why risk having to hire lawyers to fight GM? But to each his own. I'll continue using Mobil1. Oh, and make sure you store all receipts in a safe place .

///DarkSide\\\

The article below was copied & pasted from an email I received from LG Motorsports. The email was LGM News dated 6/6/12. Interesting read. Lou/Anthony - chime in if necessary

I will note my own observations at the track: a large percentage of the teams that are running track only cars (Corvette's, Mustangs, etc.) in TT's or test/tuning in HPDE's for future races, cars with essentially the same engines as we're running, most are using Red Line or Amsoil & very few run the standard Mobil 1's of the world. True, they're not worried about warranties, but you can be darn sure that they're concerned about reliability & longevity.

Engine Oil Tech

Over the last couple weeks we have done a quick look inside valve springs and how to care for them. One way to care for your springs as well as your engine is by using high quality lubricants. Over the next few weeks we will have a guest speaker from RedLine engine oils, Cameron Evans to provide a bit more technical info.

As part of a series for our longtime friends at LG, Red Line Synthetic Oil is thrilled to bring you important info on how oil works in the applications specific to the Corvette and Camaro world. Our staff members have owned lots of 4th Gen Camaro's, C4, C5, C6 and related vehicles. We live for this stuff.

We think you'll find that when you know more about why certain products are on the market, how they act in the engine, and what chemicals help them to do it, you'll make smarter buying decisions. Your parts will last longer and your car will perform better than ever. There are many good products and brands out there, and for the most part, you get what you pay for. If you are serious about performance and invested in components beyond stock, you'll learn to invest in the right lubricants based more on raw materials and characteristics and less so on brand. Here are a few points to help you get up to speed.

This first installment touches on the "big topic" of wear caused by oils lacking the certain raw materials or additive packages. In LS engines with hydraulic roller valvetrain, oils that maintain viscosity under extreme conditions are the biggest help to protecting your investment. Check for bigger numbers in the high temperature/high shear (HTHS) ratings on a oil's technical data sheet and you'll see that dramatic difference in protection-like the difference between a casting and a forging, the base stock with which an oil is created makes a big difference and the conventional oils (think cast iron parts) and blends don't cut it in your serious performance scenarios. Mobil 1's PAO base stock isn't bad for the money, but we think your own research will show that products like Red Line or Motul's 300V truly excel. Ester-based products like these can help your valve spring life by with improved heat transfer to the oil and film strength helps roller tips, cam surfaces engine generally improves.

Where API-certified products can't keep up are in the levels of antiwear additives like of zinc dithiophosphate (ZDDP). Performance-minded folks avoid API-certified products (with the "donut" on the back) as the API now limits ZDDP levels to approx. 600 to 800ppm. Though Red Line motor oils are suitable where API SN, SM or SL is called for, Red Line does not submit to these certifications so that we can increase those ZDDP figures to around 1200ppm in our passenger car motor oils (blue labels...) and around 2200ppm racing oils (the LG guys usually run our 40WT Race Oil). Note that in stock or mildly modified hydraulic roller LS engines, ZDDP isn't a giant issue. When the valve spring pressure becomes much higher than stock to support a bigger camshaft and more revs, or in flat tappet scenarios, you'll see more wear with oils that feature less ZDDP. By the way, the solid roller setups wear much like the hydraulic rollers in that they need film strength more than ZDDP, but again when spring pressure rises you'll be glad to have that extra ZDDP.

Selecting a lubricant with more viscosity is an obvious a way to get more film strength, but it's not always a great choice when you consider the gains when selecting the right product in the same viscosity. GM's LS engines are built with clearances and oil systems designed for 5W30 motor oils. The early engines that shipped in Fourth Gen Camaros and C5 Corvettes did not have the sophisticated dry sump oil systems of the latest Fifth Gen and C6 cars, so the early cars suffer power losses from windage issues when 40WT and 50WT products are utilized as attempts at avoiding wear (note that we refer to the operating viscosity and not the cold flow, whether its 0W30 or 10W30, they work them same when finally up to temperature). With the dry sump systems in the later cars, you can actually get away with running a heavier oil like a 10W40 unless you see very low oil pressure under hot temps at idle. In all of our testing with modified LS engines, we've never seen an example that needed a 50WT product.

Remember that heavier oils take more time to get up to temperature-a motor oil's additive package is heat activated, so running around with cold temp means both wearing out the engine and isn't allowing the motor oil to trap contaminates. If you can't get the oil to 210f after serious operation, you need to look into running 30WT oils to avoid unnecessary wear and sludge. Also note that thicker oils trap temperatures, so pay attention to your oil temp gauge.

Next time we'll talk about gear oils, or better yet, ATFs, in manual transmission. That's right, your manual gearbox likely is built to run on automatic trans fluid.

Have fun, go fast,
Cameron Evans of Red Line.

AORoads

Thank you, Joe, for the quotes from GM. I see now where they've made a change for earlier C6s. I guess that means I can safely go to blended synthetics such as Dexos 1, but there's nothing wrong either with using full synthetics, too. Mobil 1's still good for my use.

JoesC5

I'm sticking with Mobil1 in my Z06. The dexos is a step up from the dino oil that met the GM6094M that was spec'd by GM for all but the Corvette and a couple of other high performance cars. 99.99% of GM vehicles called for the GM6094M, so to have their full line of vehicles be able to run the extended mileage they spec'd the dexos1 synthetic blend oil. When they had the GM6094M spec for most of their vehicles they had to then have the GM4718M spec for the Corvette, due to the early Vettes not having oil coolers. By specing the dexos1, they eliminated both the GM6094m and the GM4718M. So, 99.99% of their cars get a better oil and .015 get an oil not quite as good but plenty good enough for it's intended purpose.

As far as cost, raising the bar for 99.99% of their cars by specing the dexos1, increased their cost, way more then the little savings on the remaining .01% they put the expensive GM4718M synthetic oil in.

The GM4718M was a little of a overkill for most Corvettes, so the synthetic blend dexos1 works fine for most drivers. The few that really run their Corvettes hard, with resulting high oil temps, would be better off continuing to use the full synthetic oils like Mobil1 that met the old GM4718M spec.

M-B got into hot water back in 1999/2000 when they put into their cars the extended mileage counter(same as what we have on on our Corvettes) but spec'd a regular dino oil be used. Many M-B owners waited until the car told them to change oil, which was way over what a dino oil could take and their engines sludged up. Class action law suit. M-B sent every M-B owner a new paste-in page for their owners manual specing synthetic oil and they all got an extended warranty(10 years/100,000 miles) on their engines from M-B.

Al Gumby

My local Chevy dealer stocks both Mobil 1 and RedLine for Corvette owners to choose from. Good Corvette service, BTW, at Russ Chevrolet, Beaverton, Oregon.

AORoads

Additional good information! I'd have to agree w. you that GM raised the standards for all their vehicles while slightly affecting the Corvette's. The effect tho on C6's may be negligible (except for those who race or use their cars very hard) as you say since most are used casually on the street.

I did know when there was an issue w. the M-Bs back in that time period, but didn't know the cause or the resolution. Very interesting.

Boomer111

Not much to add but for the record I run Amsoil Signature changed yearly with around 5000 miles and plenty of oil disc % left.

Also I am not worried one bit, and I tend to worry some.

I also change the diff oil yearly and the manual gearbox oil every other year.