if you look at the world factory manual, the whole gamut of oil weights is being used and based on temperature.

 

Well.... despite the clear information on the chart provided above, there must be a technical reason why Mazda recommends 5W-30 for the 2.5Turbo engine when the recommended oil for the 2.5NA engine is 0W-20; as recommended on the oil filler cap. I have to continually remind my shop to use 5W-30 in my CX-5, but that the Mazda3 Sport with 2.0NA Skyactive uses 0W-20.

 

Your information is limited to where you live in the world. You may do a couple things? First read the dozens of threads about motor oil choices and why.
Learn about why a specific viscosity should be used and it is not always the best by what the "OIL CAP" says to use.
Then and this is a BIG one and spend a few days and learn about Turbo Chargers and the effects of different viscosity choices with them.
Then learn about engine efficiency regarding emissions and MPG and what will be the best viscosity to improve both of them with w specific engine. As well how some auto manufacture gets their mandated emission within allowed specification by a specific oil which may not always be the best choice in a certain operating conditions and environment or even available in that area of the world.
Then go read and complete take in the meaning and understanding of the Magnuson–Moss Warranty Act (P.L. 93-637)


Or for you ................just use what you think is best for you based on the oil cap recommendation!

 

Imo, i wouldn't want to use anything other than the recommended 0W-20 during the warranty period. After warranty, I might switch to 5W-30 as it's an alternative for other countries in the manual. Due to new engine clearances and tolerances, I would never risk putting 5W-40, 10W-40 or other heavyweight oil in any new engine unless it called for it as an alternative in the manufacturer specs. It is understood they might use 0W-20 to merely meet cafe regs in the US. However, if the engine was designed to handle 40 weight oil, then they would put it in the manual as such for other countries with less regulations. You should probably go no thicker than 30 weight.

 

LOL you do realize that your information is all personal and not empirical and has no support based on any known facts!
Also Mazda only recommends what oil to use and that they will honor the warranty even in countries that only none synthetic motor oils are used.
I suggest revisiting the meaning of the definition "to recommend or recommend" and "REQUIRE".

Now if the auto manufacture said REQUIRED that would be totally different.

There are actually fundamental flaws in the initial service of the motor oil and filter which we have seen empirical documentation via oil analysis regarding. And Ii might add very few auto manufacture even Mada give a break in period for the engines and transmission anymore. These engine DO NOT have ceramic piston rings with total seal compression top ring and a plateau finish hone ROLMAO they doi require a proper way to break the engine in!!!!!!!

The proper way and the best way to choose a motor oil DIY rad the DIP stick ( what does slang mean when you call someone a DIP STICK? ) unless there is specific REQUIREMENTS and worded exactly REQUIRED is choosing the viscosity based on operating environment.
Oh and one last thing people who use the term when discussing motor oil as thick or thin define totally their lack of knowledge and experience about motor oils. !!!

 

Maybe i am reading this wrong, but doesn't this Mazda manual say you can use a 40 weight?

 

Yup! And it has been posted on a few threads as well other MAZADA forums and even a forum that is OIL/Chemical related!

 

While your above message is noted and your critique on difference in wording , i. e required versus recommended is also noted... In the real world, big companies have all the power and they already deny warranty work based on the simplest of reasons. If the empirical evidence you state exists for you to use 10W-40 in your engine then so be it. But why would anyone give any reason for any large company(regardless of the product type) to deny warranty repairs ? Why make extra work to have to file lawsuits to get something done merely because you didn't use the recommended oil? And then argue required versus recommended in court ? Spend your kids college money to get your car fixed? If you have the kind of money to take on the companies retained staff lawyers then so be it but the rest of us don't care what the empirical evidence says about sticking 40 weight in their engine until maybe after the warranty expires.

And I realize the difference in viscosities but it's easy to use slang for thick versus thin...most people understand the simpler wording.

Lastly I'm not questioning your expertise in said area but why roll the dice on expensive warranty work???

 

Name one instance in the last 50 years any auto manufacture denied an engine warranty based on them claiming that the consumer used the wrong viscosity oil other then when it had a required viscosity.

 

Not quoting any one member
Often times when I see responses on various forums from a member I look into what the member has posted in the past. I am aware of most your responses and they are full of opinions and personal thoughts. In many cases you let the dealer work on your vehicle and interpret according to the post seem to always have problems after a service from them? So I do get the DIY thought approach when members post but your consistence defending a thought that is not in any way factual is just funny if not ridicules? Most members that come to forum seek advise ,help and just post their adventures with the platform, but there are a few members that think the world is based on myths and a support system from others that really have no clue how things work in the real world let alone any depth of experience in the subject materiel of some threads. So rather then sit back and just read they will blindly defend their responses with more unfacts and DIY myth based concepts and information even when presented ways to get of the forum and do some real fact finding for empirical information.

Motor oil choice has and will remain a mystery to many of you and the current MTYTH formed over decades will be continually supported by more members responding to their mythology wisdom and experience.