# Talk me out of running 0w30 in my Ecotec3 **URL:** \ **Category:** General Discussion\ **Created:** [August 25, 2026, 8:15pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121 "2026-08-25T20:15:00Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![ChrisTheTireWhisperer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/christhetirewhisperer/32/34798_2.png) [@ChrisTheTireWhisperer](https://community.cartalk.com/u/ChrisTheTireWhisperer)\ **Post date:** [September 9, 2026, 2:07am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/21 "2026-09-09T02:07:22Z")
I believe the word ‘water’ is being used as a tongue-in- cheek reference to the low-viscosity oils used in many modern vehicle engines. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 9, 2026, 2:18am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/22 "2026-09-09T02:18:39Z")
When draining 5W30 @ 150 degrees it flows faster than water. Why should engine oil be thicker than water? Water is not a baseline for oil standards. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 9, 2026, 2:37am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/23 "2026-09-09T02:37:45Z")
Ive been changing 0-20 oil for ten years and never noticed any iissues. Gotta remember though zero is the cold weight. Once heated, its 20. Spend dome time with the oil geek though. ---
**Author:** ![ChrisTheTireWhisperer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/christhetirewhisperer/32/34798_2.png) [@ChrisTheTireWhisperer](https://community.cartalk.com/u/ChrisTheTireWhisperer)\ **Post date:** [September 9, 2026, 8:13am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/24 "2026-09-09T08:13:25Z")
I’m so old… I’m so old my first two cars required _10w40_ oil! 😆 ---
**Author:** ![JoeMario](https://avatars.discourse-cdn.com/v4/letter/j/3bc359/32.png) [@JoeMario](https://community.cartalk.com/u/JoeMario)\ **Post date:** [September 9, 2026, 1:53pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/25 "2026-09-09T13:53:28Z")
I think I’m in good company on this site when I say my first car specified - SAE 20 or 20-W in normal summer weather, - SAE 30 above 90 degrees F or high speeds, - and SAE 10-W for winter. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [September 9, 2026, 3:50pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/26 "2026-09-09T15:50:02Z")
In Wisconsin in January my Dad would run 5wt non-detergent in our Flathead six. My first generation Coyote is out of warranty, next oil change it may get 0w-30 0r 5-w30 full synthetic rather than the 5w-20 blend. As far as everybody else, if the car is out of warranty run what you want. As far as I’m concerned you can run Mazola or Karo syrup. ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [September 9, 2026, 4:26pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/27 "2026-09-09T16:26:13Z")
> [@Old-Days-Rick](#): > > I put 0w30 and after 500 miles everything is A-OK Good to see a robust verification plan has been executed. 😛 When the designers decided to use the thinner weight oils to increase efficiency, it wasn’t done in exclusion to everything else. That system is designed as a whole to use that specified oil. In fact, to take advantage of it in other ways. For example, the design interface tolerances can be made much tighter as a result. A thicker oil will take longer to properly access and lubricate those interfaces resulting in increased wear. The thinner oil is transferring heat more efficiently and the engine design takes this into account. Using a thicker oil risks overheating critical areas. This will not be immediately obvious. For example, increased wear on the rings, turbocharger bearings, breakdown of the oil itself… Many modern designs use the oil as a hydraulic control fluid and thicker oil prevents these systems from working as designed until the oil heats up enough. The list goes on. Trying to outsmart the people that designed it usually doesn’t end well in the long term… ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [September 9, 2026, 7:42pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/28 "2026-09-09T19:42:56Z")
I don’t believe any oil becomes thicler (heavier) as it gets warmer. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 9, 2026, 8:20pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/29 "2026-09-09T20:20:22Z")
That is what the multi weight means as opposed to a straight weight, but ill check again. You can do a quick goggle for an AI answer plus a video but excuse the english accent. A lot of that going around. If you want an engineers answer then see the oilgeek. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [September 9, 2026, 8:39pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/30 "2026-09-09T20:39:36Z")
All oils get thinner as they get warmer. Multi-grade oils (take 0w-20) act like 0 grade at cold temperature (1 mm2/s at -40C) and like a 20 grade when hot (9 mm2/s at 100C). But it’s still far thinner when hot than when cold. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 9, 2026, 9:20pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/31 "2026-09-09T21:20:23Z")
Well duh, but it would be the same viscosity with a straight 20wt as a multi weight a engine temp. Now to complicate a little, the oilgeek talks about the ability for the oil to stay in grade. So you may think yo have a 30 weight but it actually degraded to a 10. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 9, 2026, 9:55pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/32 "2026-09-09T21:55:51Z")
> [@Old-Days-Rick](#): > > I put 0w30 and after 500 miles everything is A-OK and I really believe the engine is a tad quieter. I put 5W20 in my 1998 Dodge Ram and everything was OK for 3000 miles, the engine was quiet, the sky was blue… No different than 10W30. > [@ChrisTheTireWhisperer](#): > > I’m so old my first two cars required _10w40_ oil! You were probably using the wrong viscosity oil, was this a vehicle from the 1960’s? ---
**Author:** ![ChrisTheTireWhisperer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/christhetirewhisperer/32/34798_2.png) [@ChrisTheTireWhisperer](https://community.cartalk.com/u/ChrisTheTireWhisperer)\ **Post date:** [September 9, 2026, 10:42pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/33 "2026-09-09T22:42:09Z")
> [@Nevada\_545](#): > > You were probably using the wrong viscosity oil, was this a vehicle from the 1960’s? '71 Chevelle in high school, '81 Buick Century in college ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 9, 2026, 11:24pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/34 "2026-09-09T23:24:28Z")
10W40 was not “required” in 1981, it was discouraged. 10W40 contains a high level of viscosity modifiers, this can lead to clogged piston ring groves. For most cars during the 1980’s, 5W30 and 10W30 were recommended as per the owner’s manual. This is from a General Motors service bulletin: ![image](https://global.discourse-cdn.com/cartalk/original/3X/f/5/f5892249e1a1ac67558ba16fee7535a1ba026698.png) ---
**Author:** ![Old-Days-Rick](https://avatars.discourse-cdn.com/v4/letter/o/7feea3/32.png) [@Old-Days-Rick](https://community.cartalk.com/u/Old-Days-Rick)\ **Post date:** [September 10, 2026, 12:56am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/35 "2026-09-10T00:56:16Z")
> [@Nevada\_545](#): > > 10W40 was not “required” in 1981, it was discouraged. 10W40 contains a high level of viscosity modifiers, this can lead to clogged piston ring groves Wouldn’t a 0w30 have the same amount of viscosity. Modifiers? ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 10, 2026, 1:17am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/36 "2026-09-10T01:17:49Z")
> [@Old-Days-Rick](#): > > Wouldn’t a 0w30 have the same amount of viscosity. Modifiers? Not with synthetic engine oil, there is a difference in oil from the 1980’s and the wide viscosity ranges offered today. I didn’t see 0W30 on the old General Motors charts. This is for 1985 Chevrolet: ![image](https://global.discourse-cdn.com/cartalk/original/3X/2/5/2515b38882f1794e1234eb665bc892fe21abc230.png) ---
**Author:** ![ChrisTheTireWhisperer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/christhetirewhisperer/32/34798_2.png) [@ChrisTheTireWhisperer](https://community.cartalk.com/u/ChrisTheTireWhisperer)\ **Post date:** [September 10, 2026, 3:20am UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/37 "2026-09-10T03:20:24Z")
Well, that’s what “My father said” to use, and that was in 1990, around the time I was driving the '81 Century. My Google search results match your statements about 10W30. Drove it for six years retatively trouble-free, being it was an estate car with under 5,000m(8,000km) on the clock. Oil, two sets of tires, one A/C recharge, one set of sparkplugs, is all. ---
**Author:** ![glasspilot](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/glasspilot/32/27886_2.png) [@glasspilot](https://community.cartalk.com/u/glasspilot)\ **Post date:** [September 11, 2026, 2:37pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/38 "2026-09-11T14:37:38Z")
My 2017 Chevy Volt requires Full Synthetic 5-20W “Dexos” oil. It is stated on the oil cap. I went to my local Wally-World to buy some Mobil 1 Dexos 5-20 and I found it but the Dexos label was gone. They had 0-20 and 0-30 with the Dexos label. Checking online it appears that Mobil has to pay GM for certification to place “Dexos” on their oil. Further searching showed Chevy saying it was “ok” to use 0-20 in my Volt. But my cap says 5-20. So off to my Volt messageboards/forums. Some guys were saying “It’s ok to use the thinner stuff”, others thought that just because Mobil didn’t pay the blood money to GM didn’t mean the 5-20 was any worse for my car than before, when it did have the label! What did I do? I bought the Mobil 1 5-20W (without the label) and have used it for years now. ---
**Author:** ![ChrisTheTireWhisperer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/christhetirewhisperer/32/34798_2.png) [@ChrisTheTireWhisperer](https://community.cartalk.com/u/ChrisTheTireWhisperer)\ **Post date:** [September 11, 2026, 7:47pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/39 "2026-09-11T19:47:15Z")
“Dexos” is marketing. 5W20 is the spec oil. Use that. One n done. ---
**Author:** ![asemaster](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@asemaster](https://community.cartalk.com/u/asemaster)\ **Post date:** [September 11, 2026, 8:18pm UTC](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121/40 "2026-09-11T20:18:50Z")
> [@ChrisTheTireWhisperer](#): > > “Dexos” is marketing. > > 5W20 is the spec oil. Use that. I disagree. 5W20 is a viscosity rating. Dexos is a durability and performance rating. Vastly different. The Dexos rating is required to ensure proper operation of the oil life monitor. Using the manufacturer recommended oil change interval without using the proper oil could lead to problems. Why take the chance? [Previous page](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121.md?page=1) [Next page](https://community.cartalk.com/t/talk-me-out-of-running-0w30-in-my-ecotec3/206121.md?page=3)