I don't get it. Why all the debate over 0W30 vs 5W30?

This is such an over analyzed issue. I really don't see the point to risk damaged to a $50,000 car by experimenting with different grades of oil.

If the factory says use 5W30 Mobile 1, use it. Nothing to be gained in my opinion.

 

GM doesn't say that you need to use Mobil 1 though, they simply list it as being the factory fill. GM has a list of recommended oils that pass the 4718M specification that the Corvette requires:

 

However, I have used 0W-30 Amsoil for years, in several Vettes, with no problem.

 

Yep, and I was using Castrol 0w30 (German version) in my C5 for many years, with stellar oil analysis results. A well built 0w30 can do everything that a 5w30 can do, only having the added benefit of better performance in extreme cold.

With that being said, Mobil 1's 0w30 is not really known for being a well built 0w30. I can't recall seeing any oil analysis results from that oil that have impressed me (to be honest, nothing Mobil 1 makes nowadays impresses me, it's not as good as it's hyped up to be)

 

I can't believe I'm just finding this post...

For those that don't believe 0w30s can perform well in LSx motors, here are four used oil analysis samples (2 from AMSOIL 0w30, 2 from German Castrol 0w30) on a 99 FRC with a modded LS1 engine from a fellow forum member:
Used Oil Analysis Comparison: German Castrol 0w30 vs AMSOIL Series 2000 0w30

And to add a little fuel to the fire that you can't judge an oils hot performance by its xW rating, below listed are a few pertinent High Temp High Shear ratings pulled directly from the manufacturer's websites. The High Temperature/High Shear Test (HTHS) measures a lubricant’s viscosity under severe high temperature and shear conditions that are similar to severe service applications in an engine.

Amsoil Series 2000 0w30 (API SM) – 3.2 (meets GM Standard 4718M)
Amsoil SAE 10w30 (API SM) – 3.2 (meets GM Standard 4718M)
Amsoil SAE 5w30 (API SM) – 3.2 (meets GM Standard 4718M)
Amsoil XL 5w30 (API SM) – 3.2 (meets GM Standard 4718M)
Amsoil XL 10w30 (API SM) – 3.2 (meets GM Standard 4718M)
Amsoil XL 5w30 (API SM) – 3.2 (meets GM Standard 4718M)
Pennzoil Platinum 10w30 (API SM) – 3.15 (meets GM Standard 4718M)
Mobil 1 10w30 (API SM) – 3.14 (meets GM Standard 4718M)
Mobil 1 EP 10w30 (API SM) – 3.1
Mobil 1 EP 5w30 (API SM) – 3.1
Pennzoil Platinum 5w30 (API SM) – 3.1 (meets GM Standard 4718M)
Pennzoil Truck/SUV 10w30 (API SM) – 3.1
Mobil 1 5w30 (API SM) – 3.09 (meets GM Standard 4718M)
Mobil 1 Truck/SUV 5w30 (API SM) – 3.09
Pennzoil Truck/SUV 5w30 (API SM) – 3.0
Mobil 1 0w30 (API SM) – 2.99 (meets GM Standard 4718M)

The Mobil 1 oils follow a trend that many above would have guessed: 0w30 lowest, followed by 5w30, followed by 10w30. That would lend some credibility to those calling for Mobil 1 10w30 over 5w30 over 0w30. But the AMSOIL oils buck that trend with all of them being listed at 3.2. For the benefits of improved cold flow mentioned above, my 06 Cadillac CTS-V with the same LS2 and in the C6 gets AMSOIL Series 2000 0w30.

 

You should all be using Mobil 1 0W40 European blend. No need to thank me.


Sometimes hard to find, but worth the effort.






Mobil Product Description

Mobil 1 0W-40 is our most advanced performance synthetic engine oil designed to provide ultimate cleaning power, wear protection and overall performance. Mobil 1 0W-40, European Car Formula, exceeds the requirements of the leading industry and car manufacturers' standards required for newer modern gasoline and diesel powered automobile engines. The Mobil 1 Technology is race proven and the choice of NASCAR racing. Mobil 1 0W-40 is suitable for light-duty vehicles world wide and has the performance reserve to protect when conventional engine oils cannot. It is the first choice at the factory for the some of the worlds finest performance vehicles: Mercedes-Benz AMG, Porsche, and Aston Martin.



Features and Expected Benefits

Mobil 1 0W-40 is made with a patented proprietary blend of high performance synthetic basestocks fortified with Supersyn Antiwear Technology, our most advanced additive system available today. Mobil 1 0W-40s wide viscosity range provides a wide range of operating temperature from arctic to equatorial. Mobil 1 0W-40 keeps engines starting in Arctic extreme cold and cleans deposits, sludge and varnish often formed in high temperature operating conditions. It exceeds demanding global industry standards and the major leading builder requirements. These credentials represent the cornerstone of the performance reserve that lets Mobil 1 0W-40 keep performing well after conventional oils cannot. Key features and expected benefits include:

 

OK, there are a lot oils that meet 4718M standard. You got me.

Let me rephrase the question:

What are the advantages in using a different oil? Power? Engine life? Improved fuel economy? Save money? To be different?

In my opinion, there is little or nothing to be gained by using anything other than the factory fill of Mobile 1 5W30. Plus, there are about 1000 more important issues to worry about other than weight and brand of oil. Does anyone have any real "proof" a different oil give better service or performance than Mobile 1 5W30?

(Adding "fuel to the fire"!?)

 

Good info. But Amsoil says it meets the GM Vette spec, and GM says it doesn't. I've been using Penzoil 10W-30 Platinum and plan on staying with it. The data supports that decision. Still, it's funny that Ferrari recommends Q-State--at MUCH higher viscosity in the 599 and 430s, but it doesn't meet the GM spec. Like I said before, for a buck a quart I'll use the Q in my Jeep!

 

Patman may disagree with me on this one, but I feel that what your owner's manual says is to use an oil that meets GM Standard 4718M, which many do including Castrol Syntec 5w30 which isn't listed above either. If you look at the list Patman posted above, it doesn't say which oils meet GM Standard 4178M, it says "registered". Your owner's manual doesn't say to use oil's registered with GM to meet GM Standard 4718M. My opinion is that the above list is a revenue generating device for GM and that those companies paid to be on that list.

In answer to Mez' question above, I feel that there are advantages, some quantifiable some not. I've seen enough used oil analysis reports, as Patman mentioned above, to firmly belief that there are oils that will result in less wear internal to the engine than Mobil 1. Question may be - does that matter? To me, less wear is a good thing. There are also other benefits such as lower operating temperature, improved fuel economy, etc that would take a really detailed test to prove.

On the unscientific side, I changed out my factory Mobil 1 5w30, tranny fluid and diff fluid in my 2006 CTS-V with AMSOIL Series 2000 0w30, AMSOIL ATF and AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 and my average daily driving fuel economy went from 12.9 mpg to 14.2 mpg and my oil temps went down 5-10F.

 

I didn't know we went to lawn mower talk now...With all seriousness here...what's wrong with sticking with what the "owners manual" says.

 

I would not use it, straight 30w is for mowers and garden tractors.

 

Correct. From my experience, lawn mower engines require non-detergent 30W oil. Follow the instructions in the manual.

 

Holy chit, I am sorry I clicked on this thread, more confused than ever.. Anyhow read all posts, glass slipper has some serious facts.

I think I will stay with 5-30 till the warranty says bye bye. After that Amsoil city..

 

There are definitely a lot of oils out there which are very good, and would meet the 4718 spec without a problem, but simply haven't been submitted to GM for their "approval". It's all about money in a lot of cases, it's just too expensive for a small oil company to try to get on this list.

With that said, I would probably still go with one of the oils on the registered list for at least the first oil change or two, just to be sure the engine doesn't have some major problem with it, and then once I'm comfortable that nothing is wrong with it, I'd switch to the oil of my choice. Amsoil is definitely very high on my list of recommended oils, it's a consistent performer, and Amsoil is always improving their formulas. Mobil 1 on the other hand, is taking a backwards step, and their oil has gotten worse since they merged with Exxon, and I would never run their oil in it's current formula.

 

Actually, my lawnmower has an LS2 in it...

 

In all seriousness, lawnmowing aside, Royal Purple has had the reputation of being the top synthetic for years. Yet, it's not to the GM standard. As mentioned before on Q-state--Ferrari recommends it, doesn't meet the GM standard. Amsoil, from my motorcycle friends, is an outstanding oil--actually product line, and I wouldn't hesistate to use it in the Vette--if I hadn't stocked up on Penzoil Platinum. Still say, change it and the filter regularly and you won't have a problem with any top line oil. Leave it in too long, and I don't care what you use, the engine will suffer.

 

Pennzoil Platinum is what I'm running in my car right now. I have seen a lot of great oil analysis results posted by others using this oil, so hopefully I will see great results too. I was a little hesitant to switch from German Castrol 0w30 since it served me so well, but curiosity got the better of me and I wanted to try something different. I'll give the PP a few intervals and if I'm not happy with the results I will most likely try Amsoil next.

I'm not a fan of Royal Purple at all. I ran it in my wife's Honda and it thinned out very quickly and showed very poor engine wear numbers in the oil analysis reports. Scary valvetrain noise at startup too, no other oil in her engine did that.

 

Interesting on Royal Purple. A few years ago all the specialty car mags raved about it. Of course, ad dollars may have had something to do with that.

 

I learned a long time ago that flashy advertising means nothing in terms of actual performance of an oil. Mobil 1 has the biggest advertising dollars, so they've managed to convince the entire world that they are the number one synthetic, and in terms of sales they are. So they've done their job well in terms of advertising. But I wish they'd spend some of that money into improving their oil so that it's performance met it's hype. Same with Royal Purple unfortunately.

 

Wrong. I have a bottle of RP 5W-30 sitting right in front of me and I quote, "It also meets GM4718M gasoline and oil performance and fuel economy specifications."