So what's the consensus on 0W40?
 

Yes I searched, and yes I did my reading. Without going into too much technical detail, for a C7 Z06 that's used as a daily driver, do I stay with 5W30 or switch to the 0W40? Again, my car is just a daily driver, but it is driven hard when I have the chance. The car has 6k miles on it, is a bolt on car making 650 wheel. I'm planning on doing an oil change soon and just wanted to know which would be the more sensible choice. Price is not a concern. Car has had 5W30 in it since day one.

Considering you live in PA, to reduce wear in cold starts, I would see benefit in switching to 0W-40 with better cold flow.

A statement from Tadge somewhere in these pages:


"As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorous and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use."

And the Mobil One is avaible for $27.99 per 6 quart case, no shipping charge, from Costco.com today.

In that brochure, they claim better protection for street use as well with less airation and better fluidity when cold. I think it'd make sense to use it even if you'll never go to track with the car, but well, it's up to you I suppose; you're OK to use the older 5W-30 : )

At my age I have to convince myself old is good! Or at least pretend it is. :)

I agree.

Be sure to only use the Dextos 2 0W40. Mobil 1 also has an 0w40 which is a european formula not meant for our cars.

GM has really managed to confuse us on this one. I believe the European Spec Mobil One 0-40 is Dexos 2. The ESP 0-40 is Dexos 1 Gen 2. Or that is what appears at GMDexos.com. They could not have made it more confusing if they tried. Well, maybe they did try and did succeed.

People keep making the same mistake. That isn't the same 0W40 oil that comes in the 2019 Cars from the factory. At this time It isn't available at Costco or any other retailer other than GM and one or two eBay suppliers. This is what the new oil looks like in the one quart containers you can get from the dealer:
https://cimg9.ibsrv.net/gimg/www.cor...4fc0010892.jpg

Note the ESP which stands for Emissions System Protection and the 2dexos which is just a backwards Dexos 2. The difference between the other Mobil 1 0W40 is the amount of ZDDP in the oil which causes issues with the catalytic converter lifetime which would increase GM Emission warranty costs during its 8 year/80K mile duration. I have this in my 15Z now. The dealer installed it when I did the required one oil change per year. It is still OK to use the 5W30 but the 0W40 works on track as well and eliminates the need to switch to 15W50 Mobil 1 for track usage. I think the price per quart at the dealership came to about $11.

Bill

To further confuse us the 2Dexos is actually Dexos 1 Gen 2 which is vastlly different than Dexos 2 at least according to https://www.gmdexos.com/owner/index.html

So apparently 2 Dexos is not equal to Dexos 2.

The part numbers for the new upgrade are:

I just realized this oil is cheaper when bought in liter packaging:
https://paceperformance.com/i-238727...0-1-liter.html

Here's hoping their shipping is cheap. In my case, I got 48 quarts of it back when Speedwaymotorsports.com sold it for $49.99/6-quart-box, before we all started buying from there, prompting them to jack up their price (to $59.99)

I am wrong. The Blue Logo that says 2 in the lower left is the ESP 0-40 and is what GM is now calling Dexos2. Apparently different than the old Dexos 2 which was primarily a Diesel spec. The Green Label for Dexos is now Dexos 1 Gen 2 which covers the recommended 5-30 Mobil 1 we have been using for years. Dexos2 is a trademark. Dexos 2 is a word group as Dexos 1 is a word group. I have sent them an email asking for an explanation of the difference in the specs.

And there are two separate licenses for Mobil 1 ESP. First is: Mobil 1 ESPExxonMobil Oil Corp.dexos2™0W-40GB1A0917015Global
Second is:Mobil 1 ESP FormulaExxonMobil Oil Corp.dexos2™0W-40D20679HJ015Global

One is ESP with a license number from GM of GB1A0917015 and the other is ESP Formula with a GM license number of D20679HJ015. Both with 0-40 viscosity, Both from Mobil 1.

Mobil 1 Oil Chart

​​​​​​https://mobiloil.com/~/media/amer/us...pecs-guide.pdf

I had the dealer switch to the new spec 0W40 at my last oil change and will stay with it.

I am trying to reconcile this statement from Tadge -
"As for the Mobil 1 0W40, it was not available when we validated these engines and, in its currently available formulation, it also contains more phosphorous and ash than we specify. So, even if we validated the 0W40 for track use, we would still have to recommend reverting to a DEXOS 5W30 for daily street use."

And the fact that the Mustang GT350 can use a quart of 5w-50 per every 500 miles.
https://www.caranddriver.com/reviews...lity-update-3/

"And then there's the oil-consumption issue: Over 40,000 miles, we added 21.5 quarts of 5W-50. That's in addition to scheduled oil changes. It's the most we've ever added during a long-term test by a long shot. Ford released a supplement to the owner's manual stating that the engine might consume a quart every 500 miles under severe use. "Severe use" pretty accurately sums up our treatment of just about any car, but particularly one with an 8250-rpm redline. And we were lucky; internet forums are rife with horror stories of Shelbys consuming far more."

Based on Tadge's statement, Ford, with the Shelby GT350 is risking a big problem with fouled catalytic converters. This just doesn't make sense how Tadge/GM can be that is so conservative and Ford can be that careless. Am I missing something?

BTW, I did look up on the forums and people have seized GT350 engines because it can burn through lots of oil(6 quarts in 300 miles!!)
https://www.reddit.com/r/Mustang/com...at_5000_miles/
https://www.google.com/search?q=gt35...w=1174&bih=878

What you're looking at Tadge's statement is regarding Mobile1 0W-40 European Formula. What is now recommended for our engines is Mobil1 0W-40 ESP, and it's a completely different formulation.

Regarding GT350, that engine's design is flawed, and the oil burning issue is only one of the problems it has. I don't see the connection to our cars, though. LTx engines are not high revving engines, not designed for it at all, and are usually pretty good (low) on oil consumption, even with aggressive use.

Splitting hairs. Lease of my worries.

So for those without cats, is there any appreciable different between the standard 0W40 Euro and the new stuff outside of the official certification?

Too much to gamble. Stick with your 5w30. Idk why people like to overthink what the engineers have already thought of.