Mazda responds 5w-30

[madar]

We are all well aware, what's stated in the owners manual is regulated by CAFE for 0.2mpg fuel savings, NOT based on what the engineers designed the vehicle around.

It's helpful to know what the engine is actually specified for, and , to consider the statement: "tight engine tolerances" as complete and utter bull, and to stop worrying about using 5w30 when the engine was clearly designed for weights beyond that. 5w30 is also a weight that was pushed by CAFE not very long ago, actually.

As for actually going beyond 5w30? I'd run 5w40 or even a 10W in hot weather. Done it before, would do it again.

That's not what I'm talking about. I'm talking about the differences between the oil chart from 2016 versus the one in this post. There's a half dozen new oil grades which aren't CAFE oils on your chart. All of a sudden Mazda is giving its blessing for these grades.

 

[CrazyHippie]

go to walmart buy 0w20 get the reciept photo copy it and then return it and get the oil of your choice.

Yep. And if asked, tell the Truth. "I bought 0W-20 for that oil change." Reciprocal honesty is the best policy.

 

[joc1394]

2025 CX-5 2.5T here. My cap says 5w30...
You could find a wrecked turbo and swap caps after you fold over the page in the back of the manual with the oil recommendations for the turbo. My manual has recommendations for both 2.5 N/A and 2.5 Turbo, it would be easy to get confused...

 

[nickswhip24]

go to walmart buy 0w20 get the reciept photo copy it and then return it and get the oil of your choice.

you sneaky dog-thats good

 

[nickswhip24]

The maintenance requirements for severe driving conditions represent a higher standard of care for the same engine. It would be difficult for Mazda to deny warranty coverage on the ground that the owner has been more careful/diligent than most.

eh,i got that from toyota with a 2011 camry-they had sludge problems and i was told i wasn't covered because i did proper maintenance-i changed out 4 oil sender switches ,paid someone to pull the bottom end of engine apart...good oil pressure top and bottom and kept getting low oil light...
i got the car used so i was screwed-yes ...i had all my receipts for self maintenance and still got Nada

 

[yrwei52]

Wow, 10w-50 is in the mix now? Incredible.

Yes, no 10W-50 in the mix in earlier days. Here’s the oil viscosity chart from Mazda CX-5 Owner’s Manual world wide back to earlier days:

 

[Lazy2.5]

Yes, no 10W-50 in the mix in earlier days. Here’s the oil viscosity chart from Mazda CX-5 Owner’s Manual world wide back to earlier days:

View attachment 382543
View attachment 382544

These charts claim that a 0W, 5W and 10W are all suitable for well over 40c+ operation.

My thought process:

- I've verified on Mazdaedit that the target oil temperature for the 2.5 is around 84c - The ECU maintains this target regardless of ambient temp.

However, during sustained WOT in 30C+ weather, oil temp nearly hit 100C, which is high for a thermally efficient engine like the Skyactiv.

Therefore, if you are driving normally, even in hot weather, assuming your oil temps do not creep past 85C, in theory, you should be getting "sufficient" engine protection with a 0W. However, I am still doubtful of this, as temps will easily increase with additional cargo, going up hill, higher RPM and throttle position, etc.

I am further doubtful of 0W in general as we know that is prioritizes fuel economy above everything else and simply leaves owners in the dark regarding how much additional engine wear it causes and whether it is truly sufficient.

Based on the fact that my engine sounded significantly quieter and smoother (Much less valvetrain clatter) When switching to 5w30 years ago, I never went back to a 0W.


Another point to make is cold starts and cold weather driving. People love to argue that 5W and 10W is so terrible for this use, although the chart clearly shows no problems unless you live in the Arctic.

For those of you that like to load the car up with your family, gear, have the A/C blasting, accelerating hard and maintaining high speeds in 30C+ weather during your road trips, I personally would advise to use 5W40 during those hot months.

If I lived somewhere tropical, like south florida, I would stick to a 10W even.

 

[N7turbo]

@Lazy2.5 why do you refer to it as 0W? The viscosity at those temperatures will be closer to 20 or 30 depending on the oil. It doesn't stay at "0" for more than a minute after startup.

 

[RedBaron]

These charts claim that a 0W, 5W and 10W are all suitable for well over 40c+ operation.

The first number (like the 5 in 5W-30) relates to the cold temp performance. It's the second number (30) that relates to the HIGH temp performance. Thus, in that table, they are all -30 weight, which is why the high temp bars all end at the same point. If you need protection at even higher temps, go to an xW-40 or -50.

 

[Lazy2.5]

@Lazy2.5 why do you refer to it as 0W? The viscosity at those temperatures will be closer to 20 or 30 depending on the oil.

The first number (like the 5 in 5W-30) relates to the cold temp performance. It's the second number (30) that relates to the HIGH temp performance. Thus, in that table, they are all -30 weight, which is why the high temp bars all end at the same point. If you need protection at even higher temps, go to an xW-40 or -50.

Right, I was referring to the Winter weights because I was also comparing how they theoretically perform in cold temps, based on the chart provided, though I did not differentiate this from the hot temp rating in my original post, correct.