Would you use 0W30 instead of 0W20?

Yes kschachn, regarding your statement, "And it isn't magic that thinner grades were listed. It was a reasoned decision based on adequate MOFT under typical circumstances." I accept your absolutely valid point. But I still maintain that if there was not the "CAFE-factor" involved, then I'm saying that GM would have just left things well enough alone. I suspect he 5W30 was working just fine.
-besides that, still like the word "magical"-
 
Considering fuel dilution, that 0w-20 gets even thinner as the miles pile. So if it makes you feel better use the 30 weights. It's what I do. If you live somewhere where temps fall really low, like in the -F, 0w-30 would be good. Otherwise don't stress and just use 5w-30. My wife's Hyundai calls for 0w-20 but I fill 5w-30 and the car runs beautifully.
 
Oh, sorry I also wanted to mention that I also read and appreciate the thick vs thin thread. Overkill really nailed it with his great information !!
It is totally logical in my mind that to go up only one step on the hot viscosity rating should be very safe and makes good sense.
Going from xW-20 to xW-30 is safe. There is absolutely no car on Earth that is going to be harmed if going from 20 to 30 hot weight. Using 0W-30 probably is a good idea in the winter if you're in Wyoming. It could be used all year round too.
 
I've been using 0W20 since 2006 & it's been fine.

Back then, I had access to every additive known to man, any & every VII (including all those of The Competition) & every type of base oil (except GTL which Shell refused to sample). I also had access to all the analytical services you could wish for...and it was all FREE!

I could have opted to make myself anything but I chose to make myself a Group III/IV OCP VII-based 0W20 with just under 1000 ppm Phos & a medium amount of Moly. There might also have been a splosh of heavy Group I as a secondary sulphur source & a provider of aromatic solvency. My 0W20 never saw the inside of a test engine but after running so many of them, you have a pretty good idea of how it would perform. I checked my used oil a few times & wear was nigh on perfect. I still have a couple of cans of it in my garage!

It's worth pointing out that a few years earlier, I'd spent an arm & a leg developing a mega-expensive 0W30 GM Factory-Fill oil. I could have picked that... but I didn't because wear-wise, I rated it as a worse option (it didn't contain Moly).

I don't believe you have to decide between fuel economy or anti wear performance. You can have both at the same time. For ordinary, civilised driving (ie not track, towing, altitude or banging along dirt tracks) 0W20 is fine...
 
I thought 0W30 or 5W30 was a better choice than the 5w20 both my Jeeps have stamped on their fill caps. I've been running either 0w30 or 5W30 oil in both of them for several years now.
I have Jeep with the 3.6 and a Ram Limited with the 5.7 that call for 5w/20 where in years prior it was 5w/30. I do like you and run the 5w/30 (Mobil 1) most of the time but have used 0w/30 Mobil 1 AFE as well. I feel better protected with the 30wt oils even though I have no data to support that.
 
How about this reason: C.A.F.E standards. -all striving for potential fractional increases in mpg.
I used to own a 2001 Ford Explorer with the 5.0L V8 engine. Yes that famous 302, designed in 1968. Initially was designed around 20W40, then transitioned to 5W30 and last years (like mine) was specified with 5W20 oil. Same oil pump and internals.
That former bullet proof engine lasted only 5 years on the 20 weight, then it started to have low oil pressure warnings at idle, with warmed engine. When I gave up that car, at 21 years of age and 200k miles (rust got it) it was requiring 50 weight oil to keep that warning off.
Peopl ethat started with 30 never had those issues.

With that same car I noticed that the more "extended" the oil range was, the sooner the warning of low engine pressure was returning - in miles since fresh oil was added. A 15W50 was lasting 7,500 miles, but a 5W50 only 3,000 miles (both synthetics).

More, I noticed that the newer oils labeled API SN grade of "Resource Conserving" are at the lower end of the allowed viscosity scale. I would say that an oil with weight 30, SN+RC has a similar/very close viscosity with a SN 20.
 
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Oh, sorry I also wanted to mention that I also read and appreciate the thick vs thin thread. Overkill really nailed it with his great information !!
It is totally logical in my mind that to go up only one step on the hot viscosity rating should be very safe and makes good sense.
And, my friend, that’s exactly what I’m doing with my Tundra.

Spec is a 0W20. But the manual says that under certain conditions, a higher viscosity may be more suitable.

I happen to like the Pennzoil Ultra Platinum, in 5W30, which I buy on sale at Amazon.
 
A good example is my car. The same engine in the TSX was originally spec'd for 5W30. The TSX is a more high performance car than my Accord,and was expected to be driven harder, which is my guess as why Acura called for 5W30 vs 0W20 in it.
 
Another good point. Thanks. -especially it spends winter nights in the heated garage.
IMO, no worries with VM with M1 or PP … Infineium (RDS/XOM JV) makes advanced VM’s including star polymers … if there were any issues … Dexos 1.2 testing would pick up on them.
0W40’s must undergo stringent Euro OEM testing …
0W’s are going to have good base stocks …
 
castrol edge 10W-30 has my vote. 6% noack 🥰

tbh i'd run whatever makes me feel cozy at night. if you think the 0W-30 is a better choice then run that.
 
Holy cow everyone !! (fitting for Wyoming,,, although I was never in any of those businesses,,,) What outstanding replies !!
I would like to acknowledge each person, but for the sake of efficiency I'll just make a general reply to all.

And maybe I need to first make these few comments: Please accept the fact that I am not here to frustrate or annoy anyone. When I deserve to be scolded, I will accept it with due respect. Forgive me if my posts get too long or unnecessarily detailed. Yes, I could have included such things as dynamic viscosity and the resultant bearing heat generated, the critical importance of oil film strength, dry starts and the industry proven resultant wear, and on and on. I just didn't feel it was necessary for the purpose my my question. I still use the old-fashioned laptop for my interface with the amazing world wide web, hence the ease of using quotes, etc. for clarity quite convenient. I'm just an old retired guy that still values learning things. I am willing to share with you things that I am discovering along the way. I have always valued quality motor oil and filters, even to the point of overkill. I am very impressed with the broad spectrum of fantastic knowledge and experience found here on BITOG.

So, by posting my question in this "new" thread, it has generated outstanding responses from many people that otherwise would not have seen my questions/comments on other threads with similar subject matter. Thank you for that privilege.

At this point I am finding it absolutely intriguing that so many people's real world experience is totally verifying the overall validity of using a motor oil that falls within approximately 9 to 12 cSt kinematic viscosity. -the properties of a typical 30wt oil at 100 degrees C. -maybe overkill, but likely good insurance.

And to that I add several other properties, in some cases not critical, but certainly pertaining to overall high quality.
Like purity of the synthetic base stock oil used, the high importance of a quality balanced total additive package, and the very high importance of the seldom mentioned, often forgotten, or just plain unaware actual factual provable film strength of the finished oil. -something that so far I have only found published from one source, a mechanical engineer, not oil company data.

I really like the concept of using whatever makes a person feel cozy at night. That is very profound advice. Especially given that there is a certain amount of flexibility in actual product used, just as long as the OCI's are always respected as being critically important.

I have a rather profound statement I read somewhere years ago, regarding the undeniable basic facts of how proper lubrication between any two moving metal parts can make wear impossible. If there is any interest, I will see if I can recall it.

Cheers everyone. Thank you for the continuing interest. Have a quality day !!
 
Like purity of the synthetic base stock oil used, the high importance of a quality balanced total additive package, and the very high importance of the seldom mentioned, often forgotten, or just plain unaware actual factual provable film strength of the finished oil. -something that so far I have only found published from one source, a mechanical engineer, not oil company data.
Please provide a reference to this seldom mentioned and often forgotten data that has very high importance.
 
OP...stick around long enough and you will come to the only correct conclusion on BITOG...99% of what is said here is pure mental masturbation with no real world significance and the 1% that is significant is being alerted that some specific brand is having a sale.

Seriously, you’ve already overthought it.
 
and the very high importance of the seldom mentioned, often forgotten, or just plain unaware actual factual provable film strength of the finished oil. -something that so far I have only found published from one source, a mechanical engineer, not oil company data.

Sometimes it is worth asking yourself WHY something is seldom mentioned. ;)
 
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