So, my buddy did an oil change on his C7 last week. Came over this morning and we're talking about how easy it is, when I ask him which oil he used in his. He says "Mobil 1". I say, yeah, but which Mobil 1? He says 0W40, to which I rel=ply, yeah, but which 0W40? He says there is only 1, to which I reply (after reading the threads here), uhhh, no, there's 2 different specs. One is the Euro formula, the other is the Dexos formula. I show him the threads and he gets all freaked out, calls his wife to go out in the garage and look at which oil he used. Sure enough, it was the Euro spec. Now he's all freaked out. Says he ruined his car. I calm him down and suggest, since he's here and I have the quickjacks down anyway (to clean my wheels), that he take one of my cars over to NAPA or Autozone or even the Chevy dealer, grab 7 or 8 quarts of Dexos and a new filter and we'll change his oil. While he's gone, I put his car up on the quickjacks and drop the drain plug and filter (what a waste, 7 quarts of $8 a quart oil and a $15 filter with maybe 10 miles on it). So we get the right oil, spin a new filter on and bing bang boom, he's a happy relaxed owner again.
But here's my stupid question of the day. What would have been the result if we hadn't changed the filter and just changed out the 6+ quarts of oil in the sump? Would the 1/2 quart or less of Euro spec mixed into the 6+ quarts of Dexos been caught by an oil analysis should a worst case engine failure have happened? (unlikely to the extreme, but anything is possible). Can that small amount of mixture be seen in an oil analysis? I mean, it's really almost the same exact oil. Same blend other than the phosphorus and zinc levels (900/990 Dexos vs 1000/1100 Euro). And the next question is, say there is a catastrophic engine failure. Can GM deny a claim even if the customer has receipts showing the correct oil and filter was used? Well, we know they CAN, but would it hold up?

 

It would have been fine to leave it.

 

^^^
I'm not sure what "fine" means in this case.
A catastrophic failure before the next oil change comes up would would be highly unlikely, but you might be mis-treating the engine and cats to some small degree if you left the "wrong" oil in place.
Blackstone has told me they sometimes receive oil for analysis from car manufacturers who are suspicious about what oil the customer had used or how often they change it, so that can happen.
And GM doesn't have to "prove" anything in a warranty claim, they just say "No" and know that you can buy a new engine cheaper than the cost of fighting them.
Look at the recent posts here about warranty denial for using the "approved" 0W-40 Dexos in a car produced before the official switch.
I think the OP and his friend handled it just right.

 

I run the euro in my car for the extra zinc. I actually run the euro in all of my cars. The dexos is supposed to just be a little better for the cats/emissions, which I could care less about.

 

I read through almost all of the posts about GM warranty denials for using the "wrong" oil. That's what made me mention it to my friend. It scared me somewhat, reading of the issues others have had either mistakenly or purposely running the "wrong" oil or filter.
I'm happy to pay a little extra for the recommended oil/filter. Do the same on other vehicles I own that may still be under a factory warranty, but have no compunction to do so after the factory warranty runs out.
My question was more about what oil analysis might be able to show, ie: could they tell if one were using Euro vs Dexos or a mix of the 2.
I spent 25 years in the car business (on the retail side) and my wife just retired from 37 years with Nissan in their parts/service side and the horror stories we've seen are horrendous from the customer side. Knowing that GM would deny a $15-20k replacement engine over using what is essentially the same oil is bullshit, but all the manufacturers do it, and worse.
Correct me if I'm wrong, but I was under the impression that when GM made the switch to Dexos2 (which I think was 2018?), it applied retroactively to anything 2014 on. Why would GM deny a claim over an oil issue if the oil used was the recommended brand/type/weight?
I guess I need to do some heavy reading up on oil analysis.

 

If he's referring to the mariomark story, it's because the dealer and GM area rep both interpreted the TSB incorrectly, at least according to most reasonable armchair quarterbacks (including me).

 

Nothing would have happened. The car would have run just fine for 100K more miles.

 

Knowing a little about oils and warranties I would make a couple of statements and a couple of guess The zinc in the oil is for camshaft wear. The more zing the less cam wear that’s a fact. Guess that Europe has lower emissions standards so less worry about what goes out tail pipe.

 

I think it depends on what the additive differences are in the two oils.
Years ago, a sloppy (or crooked) dealer had their bulk tank half full of Mobil1 5W-30 like it was supposed to be, and half full of some other 5W-30. Blackstone flagged that immediately on the analysis after my next oil change.

 

https://blog.amsoil.com/why-do-europ...special-oil-2/

 

Nothing. Mobil 1 is Mobil 1......

 

Well, you're half right.

 

In reading the replies to that page view, I came across this:You’re perfectly safe using AMSOIL synthetic motor oil in your GM vehicle that calls for an oil that meets the dexos1 Gen 2 specification. Our oils meet or exceed the performance requirements stipulated by dexos1 Gen 2, and are backward compatible with GM dexos1. You can use it without fear of losing your new-vehicle warranty. If someone at the dealership or mechanic tells you otherwise, call us at 715-399-TECH and we’ll set the record straight.

While AMSOIL synthetic motor oils meet or exceed dexos1 Gen 2 and are recommended in engines calling for that spec, they aren’t on GM’s list of approved oils for the simple reason that we refuse to pay GM the exorbitant fee it charges to appear on its approved list. Doing so would incur higher costs, which inevitably end up passed on to you. It would also allow GM access to our motor oil formulations and hinder our ability to adjust our motor oils periodically for better performance when new lubricant technology emerges. Simply put, we formulate for performance, not third-party approvals.
Which begs the question, if one were to put Amsoil into their C7 and had a catostrophic engine failure that was oil related, according to many here, GM would void the warranty and refuse to pay for an engine replacement. Does that mean that Amsoil would step up and cover it? Reading the above, it seems like they're saying "pay no attention to the GM man behind the curtain", "we SAY our oil is OK for you to use, so use it and if the bad old GM counter person says otherwise, tell him to call us and we'll set him straight".
I see catastrophe written all over that.

 

I own a 2017 Stingray [non-Z51]. I change my own oil and use the Mobil-1 5w30 synthetic with an AC PF64 oil filter. The bottle has the "Dexos" logo on the front and is the factory fill. I have used Mobil-1 for thirty years now in several vehicles. No reason to try to fix what isn't broken.

After the second "free" oil change, my girlfriend's 2019 [also not a Z51] Stingray will get Mobil-1......but in the "Dexos" 0w40 viscosity. Even though both our cars have the same engine, hers has "0w40" on the oil cap vs 5w30 on mine.

As both are under warranty, I am going to stick to the plan. I know I can also use 0w40 in my 2017 if I want to..

As for Blackstone Labs,, I know a lot of people swear by them.. If I used the "Euro" 0w40 by mistake, I would probably change it out and put the right stuff in ASAP. I doubt the "wrong" Mobil-1 0w40 would do any damage, but it would still haunt me and I'd be afraid every time the car made an odd noise. I can sometimes be a bit OCD about the wrong things - and that would be one of them for sure.

There are times when peace of mind can cost you a few bucks.....but with a Corvette, I think it is worth it.

 

OP, Your friend just wasted 7quarts of new oil & a filter

 

Hey Guys, Having owned a race machine shop for over 20 years I can tell you running an oil with more zinc in it will never hurt your engine.. The powers that be made the oil companies remove the zinc for emission purposes. Having lived through the years when they first took zinc out of regular oils and trying to make a flat tappet camshaft survive in a performance application was a Supreme challenge. The hydraulic roller cams were supposed to be able to survive without the high zinc levels, but having seen hundreds of camshafts in these LS style engines that had extreme wear on the lobes, the added wear protection from the zinc could only help. It certainly isn't going to destroy your engine. Is is bad for the catalytic converter, yes I was told it would eventually plug them up. Would Gm deny your warranty for what type oil you run? We all know they will do what they want to do. Most of the dealers I dealt with just want to see that you DID change the oil regularly and it certainly shows once you open an engine up. At the end of the day GM is playing a trade off game, the govt is telling them they have to pass this emission level and they have to make thier engine live past the warranty date. If you ran a higher zinc oil and plugged the catalytic converters up before they ran out of warranty, they would prob not cover them. I have not looked at the difference between the dexos and the euro oil but if the only difference is a little more zinc in it, it definitely won't hurt your engine or your cats.

 

That could very well be true. Remember, however, that many Corvette owners are very obsessive when it comes to taking care of our cars. Even though the slightly different blend of oil would probably be just fine for his Corvette, it still might "bug" him every time he drove it.

About 2 years ago, I got caught in a rainstorm when I was about 15 minutes from the house. It is probably the only time my Corvette ever got the least bit dirrty. I put it away dirrty in the garage. There was obviously not any harm to the car, but it still drove me nuts until I could give it a thorough wash job two days later.

It doesn't make sense to most people, but I could definitely understand why somebody would be concerned about using the incorrect blend of motor oil......even if it would not do any harm. It is not unlike having a scratch on your Corvette that is almost invisible & most people wouldn't even notice it.......but YOU still know it is there.

 

He may have. I didn't. Put it back in some spare Mobil 1 jugs that were in the shop and I'll use it in one of my other older vehicles. Waste not, want not.

 

Very smart idea!!

 

Some people in this thread are overthinking this.

The motor oil will perform its primary task to lubricate. On top of that, it'll still provide additives to perform secondary tasks (antioxidants, detergents, rust inhibitors, etc...) like any other modern synthetic. Biggest difference will probably be friction modifiers and they won't be that significant.

There's absolutely zero chance that the euro 0w-40 would do even a drop of damage.