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So......I have a 2017 Stingray and my girlfriend has a 2019 Stingray. Both cars were purchased new and both of them are equipped with the 6.2-liter LT-1 engine. Both cars are of the 'wet sump' variety (non-Z51). Mine has 10,700 miles on it and I have had the oil changed THREE times now. Every oil change was done with Mobil-1 5w30 synthetic and that is also what came in the crankcase from the factory. My oil cap even has 5w30 on it, if I remember correctly.
My girlfriend's car - a 2019 - has a different oil cap on it. I think it has the Mobil 1 logo, but am not sure if it says 0w40 on it. Maybe that is what they put in it at the factory. Not sure, though. She has 1,600 miles on it - barely broken in.
If I intend to change my oil myself (since my three 'free' ones have been used) in October or November -- well before turning 12,000 miles on the car, should I stick with 5w30 or spend more money for the 0w40? When I change the oil in my girlfriend's 2019, do I have to use 0w40 to keep the warranty valid? It just seems bizarre that GM would recommend two different oils for the same engine. By the way, both of our cars are "garage queens" and will never see a track. My gut instinct says the Mobil-1 5w30 is more than adequate. (I have used that viscosity in several vehicles over the years with favorable results.)
Am I nuts for thinking that 5w30 will be good enough?
I agree with others who say you’re fine with 5W30. I could probably have expanded a bit on post #11 by saying that I think what got GM into the pickle of the silly oil switching thing is that they were successful in boosting the pushrod V8 to very high power levels, which in turn boosted it to very high heat levels when used aggressively like on the track. An occasional brief excursion with oil temp over 240F, or for that matter even 260F, is no big deal for a full synthetic oil. But if you stay on the throttle to the point that the oil temp spends a substantial amount of time in the mid to upper 200’s, there’s a problem that could get them into a lot of warranty claims. Hence the dual recommendation.
Very wide range oils like 0W40 have been around for a long time, but GM, like me, knew that the VI improvers needed to reach that wide a spread wouldn’t last 10,000 miles. So what should they do? If they recommended wide spread oil for everybody, they would be risking high warranty claims by the 90+% of people who don’t need the high temp protection but might get into trouble by the VI improvers failing. Orrrrr, they could say 5W30 (which doesn’t need VI improvers) for everybody, and risk warranty claims from the few people who do routinely drive hard enough to get their oil really hot. That’s almost certainly how they got to the dual street/track oil recommendation.
I hope (but have not yet seen data to prove) that VI improver additives have gotten enough better since my 2010 retirement that they will now last for 10,000 miles. Most of the guys who have posted used oil analyses of the new 0W40 either haven’t specified drain mileage, or have admitted it was a drain interval in the 3-6000 mile range, not even remotely close to 10,000 miles. So what do I recommend? If your run your oil close to zero on your oil life monitor and your oil seldom or never gets over 240F, stick with 5W30 until or unless you start seeing used oil analyses showing that the 0W40 has held viscosity to 10,000 miles. There’s little or no benefit to the 0W40 for normal drivers whose oil seldom gets over 240F. If you do get your oil over 240F frequently or for long periods of time, use the 0W40, but don’t run it any more than 5000 miles until or unless you see 0W40 oil drain tests on the forum that have held viscosity to 10,000 miles.
I’m not knocking the 0W40 or GM’s decision to recommend it. If it holds its viscosity for 10,000 miles, it does give a bit of extra cushion on oil temp. I’m simply saying that I know it was not possible to make a 0W40 oil in 2010 that would last 10,000 miles, and I also know that the VI improver additives needed to make that wide a spread have a long history of stability problems. That does not rule out the possibility that VI improver additives today are significantly better than they were in 2010. But if you driving habits don’t get your oil hot enough to need the 0W40, why take the chance? And as far as the warranty claims issue, they say that for street use (ie, oil seldom getting over 240F) 5W30 is acceptable.
Sure you will probably be fine with the 5W-30, however considering the benefits spelled out below for the 0W-40, I don't see the point in continuing with the 5W-30. If you can afford a $70k sportscar is the extra approx $55 per year an issue.
Last edited by Kevin A Jones; Sep 8, 2019 at 06:09 PM.
I posted once before on that topic. I think it’s mostly corporate pride. The silliness of changing oil for track use had to be galling to the GM high mucky mucks. This lets them eliminate that embarrassing recommendation. Seems petty, but I was high in my company’s corporate ladder, just one of the oddballs that got there doing technical rather than management work. While I’m proud to have worked for my company and think they rate high on the corporate ethics scale, people are people and I saw that kind of decision more often than I like to admit. Now, is the 0W40 a bit better? Sure, assuming of course that VI improvers really have gotten better since my 2010 retirement and it holds its viscosity. But does it offer any consequential advantages to the average Vette driver? Doubtful. Am I using it in my own CTSV Caddy-Vette or my wife’s BMW 550, whose oil temps only get above 240F in an occasional burst of enthusiasm? Nope. In my opinion, for my driving habits, it’s not worth spending extra for.
Chevrolet publishes a five page guide on how to prepare your C7 for a track event, and how to return it to proper condition for street driving.
The guide includes inconvenient items like:
Flushing the brake fluid to DOT4 for the track and back to DOT3 when finished.
Burnishing the brakes
Changing alignment settings & tire pressures to track and back to street when finished.
Removing front license plate bracket and reinstalling when finished.
Overfilling oil and draining back to normal when finished.
Removing the mandatory oil change from the list seems like a rather minor issue, I think there's more to it than just corporate or personal pride. I think they believe that the new 0W-40 is indeed better for most engines most of the time. Too bad we didn't get a more detailed explanation.
Yeah, I am thinking that 5w30 will be adequate for both of us.......especially since neither car will go beyond a 3,000 mile interval for oil changes (because we don't drive them very much). Neither car will ever see a track.
I'll keep using 5w30 in my 2017 and am likely going to use it in my girlfriend's 2019 as well. Mobil-1 is a great oil and should be sufficient. According to our oil temperature gauges, it stays around the 220 degree mark. Going for long drives in the country is not exactly hard on a car, eh?
This forum is a great wealth of information. Thanks to everyone here!
I’m not knocking the 0W40 or GM’s decision to recommend it. If it holds its viscosity for 10,000 miles, it does give a bit of extra cushion on oil temp. I’m simply saying that I know it was not possible to make a 0W40 oil in 2010 that would last 10,000 miles, and I also know that the VI improver additives needed to make that wide a spread have a long history of stability problems. That does not rule out the possibility that VI improver additives today are significantly better than they were in 2010. But if you driving habits don’t get your oil hot enough to need the 0W40, why take the chance?
But it doesn't need to last 10,000 miles because the OLM will not let you get that far in a C7. Most people won't even get past 8k before it counts down to zero. I'm at around 7200 miles since my last oil change (in Oct 2018) and my oil life is at 6% right now. So I'll get nowhere near 10,000 miles. I'm still running the 5w30 version of ESP Formula M1 in mine though, so it's viscosity will be more stable than the 0w40 anyways.
But it doesn't need to last 10,000 miles because the OLM will not let you get that far in a C7. Most people won't even get past 8k before it counts down to zero. I'm at around 7200 miles since my last oil change (in Oct 2018) and my oil life is at 6% right now. So I'll get nowhere near 10,000 miles. I'm still running the 5w30 version of ESP Formula M1 in mine though, so it's viscosity will be more stable than the 0w40 anyways.
It looks like we are both getting around 76 miles for each percentage point, so the OLI would hit zero around 7,600 miles.
If you only drove the interstates at moderate speeds, you might be barely able to get to 10,000 miles, but I doubt it.
Our oil change last week was at 6,700 miles on the oil, with OLI at 10%. ESP 0W-40, but the OLI doesn't know or care.
About half of those miles were on a looong road trip, the other half on suburban/rural driving.
There was one autocross weekend (28 runs through the course) and the OLI didn't change at all; the layout was such that I only got up near redline once per run and never above 220'F oil.
I sent a sample in to Blackstone but no results yet.
Of course, the big question is not how well the oil holds up in miles, but in OLI percentages.
My previous change was at 15% OLI and Blackstone told me I could have gone longer. This one at 10%. I plan to keep increasing use by 5% on the OLI each time until I hit one at 0, or until someone else reports problems.
