Did you look at your filler-cap? GM put 10W-30 on mine and if it was good enough for street driving when they made it, it has been good enough for me... without issues ever since.

 

What year/model Corvette do you have?
I'm not aware that 10W-30 was ever the recommended oil for a C7.

 

You sure it was the right cap for your car?

 

Interesting, you go by printing, on the oil filler cap and not GM's updated info, the people that designed the car and have updated their requirements on the C7.
OOPS! I guess I do the same thing. I go by the filler cap on my 2014 also, sorry.

 

You walk the talk.

 

Updated isn't the right word. I'm not sure how you don't get this. Modified, added, expanded. Updated implies that the old items are obsolete, they are not.

 

AFAIK, it helps if you are racing and street driving so you don't have to drop the oil ASAP from 15W-50 to 5W-30. Maybe it might help 4hr cat live longer but not sure. Either way, I'm not seeing any data on how it is worth the extra cost and effort to get that special oil.

 

I agree. My whole take is GM "thinned" the oil to please CAFE standards, realized it created bearing problems, then "thickened" it to try and fix it while still keeping the 0W. Problem is it will "thin" sooner than later. My use of 5W-30 has all the protection AND I don't have to worry about it "thinning" out. But again, I don't care what people use so if someone wants to use 0W40, go ahead. I have enough data to backup my decision making, not just "cuz GM recommends".

 

Does CAFÉ matter after the car is produced? IOW what's affecting CAFÉ? Today's car or a car. 10 years old?

 

I guess GM needs to come out with some statistics on the before and after the oil spec change, on how many LT1 engines were self destructing. Maybe compare the 2015 to the 2019 engine. And also give more info on the development of the 0W-40 with a different formula that doesn't break down as easy as the 5W-30.
Good info:
Mobil 1 0W-40 Supercar oil is designed to resist breakdown slower than standard 5W-30 oils, especially in high-performance, turbocharged, or track-driven engines. Its formulation provides superior shear stability and heat resistance, maintaining a thicker oil film under high stress. While 0W-40 Supercar handles heat better, 5W-30 is generally better for fuel efficiency and cold start flow.
If you want fuel economy, use 5W-30.

 

I'm assuming, but I would think CAFE matters for future cars. How far in the future? I don't know but I could see the next model year being applicable. I could also see some deal with the gov to allow carmakers to include a few previous years if it was the same model. The guy in the videos posted above mentioned that he did work with GM on an oil, I don't remember the details. But he said it was either to fix what they did for CAFE or to meet them. Thinner oil, better gas mileage. Worse for the engine but the Gov doesn't care. That's why all cars are made of plastic now and use 0W oil.

 

So my 2016 gets say 17 mpg. Today, they find this oil that gives it 18 mpg. I don't think it is going to be retroactive. It might help CAFE in 2019 but I have a hard time believing it can do anything for 2016 numbers. Also, not sure how it can meet it if it didn't unless you are suggesting the government gave them 3 years to fix what they reported? That sounds pretty close to a conspiracy theory thinking.

Sure. That said, for a 1960 car, 0W may not be a good thing but we are engineered different today. Back in the day, you need to warm up the car before driving. Today, I fire up the car, back out of the driveway and drive normally (sanely) and might WOT say a few miles down the road.

 

Changing the oil for a car that is only 3 years old does make sense. The only thing thinner oil does is lessen the resistance the engine internals have to deal with. Easier to turn means less power need to turn it, means less gas needed to create that power. It's minuscule but averaged over a fleet it adds up. So that's why I could easily imagine a car maker asking the Gov to take credit for changing the recommended oil for previous years (within reason). There is no other reason to recommend 0W40 for a 2014. It has nothing to do with thickness as showed by LDB. The only other reason would be CAFE.

Yeah, I have a '66 that doesn't work so I don't have to worry about oil at the moment, but I'm pretty sure I read from a reliable source that the oil really should be different for older cars than newer cars. They work differently. I can't point you to any data, but I think you see the difference too.

Anyway, I'm done with this thread. Thanks LDB for clearing things up.

 

I understand all that about the oil, friction reduction and that it can improve CAFE for 2019 but try as i might, I haven't heard of anything besides people speculating on the benefit of changing the oil spec for 2014-2018. If you have something documented that shows how GM benefits retroactively, I'd love to see it.

I thought the reason for the 0W-40 was so you don't have to change oil after tracking it with 15W-50?

 

I never said I was an insider. I do know that car makers and the gov have to work together, so it wouldn't surprise me. I've also only heard speculation on the benefit for recommending a new oil spec, just like you. But none of that matters. That said, this was my whole point for even posting on this thread....I use 5W-30 for the reasons explained by LDB. That's it.

 

Guys talked about some specs of the oil? Shear spec (HTHS) on MOBIL 1 0w-40 supercar is 3.53, which is min, similar to dexos 1 Kirkland 5w-30 (3.1).

You don't need 0w unless you live somewhere you have to start your car on negative temperature. 30 to 40 viscosity is useless figure unless the oil can be stabilized passed 3 to 4 k miles, where it remains 40 weight.

Been looking at a lot of oils. Best I came out with it is the Pennzoil ultra premium 0w-40 (shear at 3.6) and Mobil 1 esp x4 0w-40 (shear at 3.8) - lots of studies on both. 40k mile on pennzoil kept the engine spotless since it's 99.5% pure oil (not PAO and Ester blend) to liquid, and mobile 1 esp x4 kept it's shear level, and viscosity to 40 for 8k miles. Both dexos r. Amsoil signature series has shear level of 3.7 but those suckers are expensive. Plus amsoil is full SAP which is going to destroy your catalytic converter soon. For low SAP, high shear, good for catalytic converter, longivity for weight, your only choice is Mobile 1 esp x4, and this is tested by Bob the oil guy or some other online folks. (pennzoil is mid sap).

You only need dexos 2/r if you plan on staying on high rpm for long time, like track days. I change my oil every 6 months or 3k miles whichever is first.

But if you must want to go spend the money, get the mobil 1 esp x4 and not supercar oil. And if you want your engine to keep clean without vanishing or carbon build up forever, use pennzoil (shear loss is moderate on pennzoil after 3k to 4k tho with esp 4k and amsoil at very very low).

Esp x4 also fixed the oil supercar oil formula for detergent additive to prevent low speed pre-ignition.

My 2 cents

 

OMG reading all the different opnions gives me a headache, I'll just stick with Mobil1 5w-30 straight from the Walmart rack.

I seriously doubt that my engine will self disintegrate using this oil. But just to be safe, I'll keep my dust pan and broom handy.

What are we going to argue about next, tire pressure, morning vs night?

 

Nitrogen vs air in tires is always good for several dozen amusing replies.

 

I don't think morning vs night is a thing. Stop posting that, please. It's temperature that really makes a difference plus sun. If the sun is shining on the tires, it can change it by 1 or 2 psi. We need to know what temperature to set the tires at based on temperature.

 

that's because there is none and it's pointless if you don't track, as "almost" all of us know.

nope, makes less than no difference. It's just based on what's being sold at that time. Obviously the 0W-40 hits the same goal of meeting the epically failed
CAFE regulation that has proven to achieve literally nothing in it's multi decade history. But that's it.