Hi.
A UK group has stated that aparently Mobil updated their guidance that 0w40 is better for the LS engine as the formula is different to the mix that was 20 years ago, the 0w40 is better than the present 5w30.
Anyone heard anything on that subject?
I have a 2006 base and just want the best oil i can get, but we dont have access to a lot of oils available in the USA.
thanks

 

Wouldn't it be GM to update any oiling guidance for their engines? Curious that Mobil would say such. Post some details.

 

I think that Mobil 1 guidance update was based on the new GM Dexos oil requirements — specifically the newest standard, Dexos R. Currently, the only oil weights that meet the Dexos R rating are 0W-40 and 5W-50.

Of course, any oil rated Dexos R on paper will be considered “better” than previous generations like Dexos 1, Dexos 2, or Dexos 1 Gen 3, etc. The Dexos R rating is also backwards compatible with all prior Dexos specifications, so in theory, any GM engine that previously required those older ratings can now also run a Dexos R–rated oil.

I’d assume that’s why Mobil updated their recommendation to 0W-40 — not necessarily because of the viscosity itself, but because Dexos R is the latest and greatest GM standard.

I switched from 5W-30 to 0W-40, and my oil pressure went up about 15-20% across the entire temperature range. Idle pressure went from roughly 30-38 PSI when warm, though I do have a Melling Oil Pump. Most would probably agree that if you can find a higher-quality oil in 0W-40 than in 5W-30, go with the 0W-40 — or vice versa.

You’re going to get a million different opinions on what oil brand to use, but if you’re limited in what’s available, list out what brands you can actually get, and we can go from there. Personally, I like Amsoil, Driven, Red Line, and Schaeffer’s, but I’m not sure how easily those are found in the UK.

 

Fantastic information there, thank you.
i want the best oil to keep my stock engine safe.
I have seen that Rockauto will ship to the UK so i have options now 😉
Probably going to stick with Mobil 1 5w30.
Thanks

 

When I bought my c6 a couple of weeks back the owner passed on a several page document about GM's recommendation specifically for the Mobil 1 0w-40 supercar oil in all modern corvettes... If I can get my hands on it to scan it I'll post the doc. Honestly I haven't read through it, so not sure if it was a GM tech bulletin or what.

 

Yeah, I don't remember where I read or saw this but the updated spec for LS and LT engines is the 0W40 Mobil 1 Supercar. But the normal 5W30 Mobil 1 is also still a fantastic oil as well. Can't go wrong with either.

 

Looks like the guidance actualy refers to C7 and C8,
This info is from ChatGPT.

Here’s a breakdown of what GM says (and what owners & oil makers interpret) about using Mobil 1 0W-40 (“ESP” / “Supercar” / Dexos-2 / Dexos-R variants) in modern Corvettes — where it's fully OK, where caution is needed, and what to watch out for. If you tell me your Corvette year & engine (C7 LT1, LT4, LT5, C8 LT2, etc.), I can give more specific advice.What GM Has Officially Approved2019+ C7 CorvettesStarting with the 2019 model year, all C7 Corvettes are factory-filled with Mobil 1 0W-40 synthetic oil. GM updated the spec so that one oil could cover both daily/street driving and track use, avoiding swapping between a lighter oil (for street) and a heavier one (for track). �GM Authority +2Service Bulletin for 2014-2019 C7s (LT1, LT4, LT5 engines)There is a service bulletin (18-NA-129) that authorises use of the 0W-40 Dexos-2 oil in all 2014-2019 Corvettes with the LT1, LT4, and LT5 engines. So if your C7 is in that range and with one of those engines, GM has explicitly said using the 0W-40 is allowed. �NHTSAOil Naming / Re-brandingMobil 1’s 0W-40 “ESP Formula” oil was later re-branded as “Mobil 1 Supercar 0W-40.” The formulation is claimed to be equivalent, and specifically engineered to meet the strict GM Dexos spec required for current high-performance GM engines. �Corvette: Sales, News & Lifestyle +1There is a Dexos-R / Dexos-2 approval for the Mobil 1 0W-40 “Supercar” formula. �cadillacforums.comTrack Use ExceptionsEven when the 0W-40 is approved, GM still recommends certain higher viscosity oils for extreme or track use:For the ZR1 (2019 ZR1 with the LT5, supercharged etc.), for maximum track performance it recommends using Mobil 1 15W-50. �GM Authority +2For some other engines, when oil gets very hot under track conditions, higher viscosity can help. �cadillacforums.com +1What GM’s Guidance Means in PracticePutting together GM’s statements and the service bulletins, here’s the practical guidance:SituationRecommended OilNotes / Trade-offsDaily driving for most 2019+ C7s and 2014-2018 C7s (LT1/LT4/LT5), street & moderate performance drivingMobil 1 0W-40 (Dexos-2 / Supercar / ESP variant)Good cold start protection, full synthetic, designed to cover both street & track usage in many cases. Reduces need to swap oil grades depending on use.Heavy track use / very high sustained temps (esp. ZR1, big supercharged or dry-sump engines)Higher viscosity (e.g., 15W-50) for track, then return to 0W-40 for streetHigher viscosity gives better film strength under extreme heat, but may sacrifice fuel economy, cold start wear, emissions/catalyst life, etc.Older Corvettes (pre-2014, or non-LT1/LT4/LT5)Use the viscosity GM originally specified; use oil that meets the required Dexos / API / GM specDeviating can risk warranty, or under-protection during cold starts or in certain operating conditions. Also check oil capacity, sump type (dry/wet) etc.Things to Double-Check / Be Careful WithViscosity spec: Make sure the oil is 0W-40 and meets the Dexos-2 or Dexos-R spec (depending on engine). Not all 0W-40 oils are equivalent. Some “European” 0W-40 oils may not be Dexos-approved. Using a non-approved oil could void warranty or reduce protection. �Stingray Forums +2Engine type: If you have a ZR1, supercharged, or dry-sump engine, check GM’s recommendations for track use. They sometimes specify heavier oil for track. �GM Authority +1Warranty / service bulletins: If there's a bulletin active in your region for your model/engine, use that. For example, for 2014-2019 LT1/LT4/LT5 Corvettes, the 18-NA-129 bulletin explicitly authorises 0W-40 Dexos-2. �NHTSAOil change intervals: Even with a higher spec oil like 0W-40, track usage (high temp, high RPM) accelerates oil breakdown. Just because the spec says “street & track” doesn’t mean you can use the same oil interval — shorter intervals may be wise for heavy duty use.Cold climate / startup wear: Thinner oils (lower “W” number) help at cold starts. 0W-40 is good here, but if you have an engine always cold (short trips in very cold weather), monitor how the engine behaves.What It Means for All “Modern Corvettes”Assuming by “modern” you mean the C7 generation (2014-2019) and C8 (2020+), here are the general takeaways:For most modern Corvettes (C7 LT1, LT4, LT5, and the C8 LT2 / other GM high output engines), using Mobil 1 0W-40 “Supercar” / ESP / Dexos-approved variant is fully acceptable and often the factory or post-factory specification for many year/models.It gives a single oil spec that works for both street and fairly spirited/track use, reducing the hassle of switching oils.Only in “severe” track-only situations or in engines with extremely high heat/load (ZR1, supercharged etc.) might GM recommend going with a heavier track oil temporarily.If you tell me your Corvette year & which engine (LT1, LT4, LT5, C8, etc.), I can check exactly whether in your case GM fully supports using Mobil 1 0W-40 all the time (street & track), or whether they still suggest having a track-oil option.

 

Funny you should ask that question, I have been using 0W-40 in my car for the past couple of years. The car sees mostly track use, the only difference I've noted is slightly higher oil pressure, not that it was bad in the first place. There may also be less blowby, I use a catch can and have since the car was new in 2012, it seems to fill less now than it had when brand new - in my view that is a good thing. The Euro version is good for Porsche and Mercedes so it should be good enough for my Chevrolet!
Also interesting to note, for the C-8, Chevy spec's 0W-40 Supercar oil that is Dexos certified. I'm not sure what that means exactly, The earlier ZL-1 Camaro's have been spec'd for it too.