Mobil 1 0W16

The term “backward compatibility” in regards to these specs is not in regard to mixing oils, it refers to engine design considerations. 6B is not backward compatible with his engine, however, 6A is. Again, this is according to the AIP, which sets the standards establishes the tests, and makes the call.

EDIT: I should add that one of the considerations is oil additives interacting with the catalytic converter. Now if that is a concern here, I don’t presume to know. But that is one of several reasons an oil is determined to be not “backward compatible”. Another is chemical reactions with system parts due to changes in additive composition. There is a lot more at stake here than most people realize.

 

Toyo has been using 0w16 since 2008
Too bad my link died
https://www.noln.net/2017/06/30/skinny-ow-16-oil

0w16 is fundamentally 0w20 with less VII and a different add pack, in Terms of his car, in the home country it would have gotten 0w16 so it doesn’t really concern me, as stated still doubtful any measurable difference will be detected.

I was planning 0w16 in my 1999 Insight (which came with 0w8 green oil in Japan). Sadly very little selection

 

That 0w-16 was not the 0w-16 of today (at least by my understanding). It does not meet the criteria for 6B (no way it could have considering the 7 new tests that were established to verify compliance). More info is available. All I did was search whether IIsac GF-5 was synthetic and found some interesting information directly from AIP. There are some good videos on engine oil capacity web site that came up in that search, that can be informative (some just kind of relate to the discussion, but are informative nonetheless).
Seriously, oil has come a long way in just the last few years and it has a lot to do with engine design, one of which is Variable Timing. Start messing with the oil and you end up with blown head gaskets (sound familiar?).

 

What's the "add pack" consist of?

 

I've used whatever cheap full synthetic oil I can find. I've mainly used 0w20 and once tried 5w30 to see if it would help my oil burn/loss. My last oil change I thought I would try amazon full syn 0w20. It was a light brown color while the other oils like Mobile and Valvoline, and Castrol GTX were almost transparent. I've also decided to buy some 5w30 Valvoline "syn blend" high mileage oil as my top off oil. As I've been towing a lot more this year. Last time I did it, I lost about 3 mpg. I guess that was a full oil change and not top off oil though, to that weight.

So lets understand the oil weight a bit. 0w-20. 0 is the cold and 20 is the hot. W is winter or weight. So lets say we have 0w20, 5w20, 10w20, 15w20, 20w20. The higher that first number is, the thicker your oil will be on startup. Also depending on your drives, your engine might not ever heat up enough to use the oil as w20. I've found in my 7mile, 20 minute drives to work, in 90F weather, I don't get over 160F engine temp.

0w16, 0w20, 0w30 0w40. If your engine is up to temp, 20 is normal, 30 you lose 3mpg, 16 you might gain 1 mpg? If your engine is worn and you actually hit max engine temps, a higher weight oil can help with blowby and quiet down the engine. It can also help under heavy loads, like towing.

Lost where I was going with this... But yeah, using 5w30 over 0w20 I lost 3mpg. Going down to 0w16 will be negligible. May increase oil burning, if doing so and actually hitting max engine temp. If your engine never heats up, you may never notice a difference.

I don't know about oil filters and so far it doesn't seem like it makes any difference, but use the Toyota OEM engine air filter. I bought some other filter and I lost 3mpg. Changing my oil weight at the time was a loss because I wasn't towing, in the least. That 3mpg loss didn't make up for topping off the oil less.

Edit:
There was a video on youtube where a mechanic was working on what I think was a Ford Ecosport or Escape with a ecoboost engine. It was having problems and I think there was more explanation about how a heaver weight fixed a lot of the problems. ...If it could be found, might give more insight.

 

I'm fairly certain in an engineering explained video he said going from 5w-30 to a 0w-20 was in increase in efficiency of around 2%. So going from 0w-16 to 0w-20 is on the order of 1% or less. Hence why I say its not probably going to be measurable. But with that said automakers go to extreme lengths. One of the big offenses, they put special oem spec'd LRR tires (made for them and not the same as some of the aftermarket acceptable LRR tires) on hybrids and electrics and even trucks that will give a 5% boost in FE while being around twice the price of a standard tire and lasting half as long. Like so bad they wear extra fast compared to a standard lrr tire and cost twice as much so in my head i just label it a cheater tire like oems putting sport cup 2 tires on the gr corolla from the factory (5,000-10,000 mile $2500 a set tires! :/) So negative ROI here.
For me when I did 0w-16 I didn't notice a difference and the cost was a bit more to where if the oil worked well it would break even on cost. Not worth it, so just have been using 0w-20.
At least for me right now, I like the Pennzoil Ultra Platinum High Mileage 0w-20. Seals are weepy on an almost 14 year old car so it gives you a bit more swell on the seals. My thinking here is I could have valve guide weep along with the weep around the seals on the outside of the motor i see. So maybe a bit more longevity on the car. Also, kinematic viscosity at 100c is pretty close to mobil 1 0w-16.