Mazda 2.5 non-Turbo ACEA A3

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Hi everyone,

First post here.

I am back in car ownership after many years leasing and I have a UK 2.5 petrol 2018 Mazda 6. Now in the US this engine has a suggested 0w20 oil in the UK it is 5W30, that is the first confusion.
My second is the ACEA A3 oil, as I see so much more choice in teh A5 derivative and reading the ACEA specifications I see a difference but not something that would be overwhelming?

I have done 8K miles and am going to be dropping the oil at 7K from now on rather than teh 12.5K Mazda have in the service books, I don't thrash the engine and literally would never dream of a red-line run!

I would like to know about your thoughts on viscosity and also A5 over A3 when I can run with the Petronas fully synthetic, or Valvoline.

Many thanks for any assistance and advice
 
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The big difference is in the HTHS (High Temperature High Shear).* A3 will be 3.5 or higher. A5 will be 2.9 - 3.5. Depending on the engine itself a higher HTHS is typically warranted when you're racing, tracking, or constant high speed driving (i.e. German Autobahn).

CAFE (Corporate Average Fuel Economy) is what drives the use of low viscosity oils in the United States. Automakers try to hit a fleetwide mpg in order to avoid financial penalties.

I'm not familiar with your Mazda but if they just recommend any 5w30 then I don't think you should worry about A3 vs A5.


*HTHS measures the viscosity (resistance to flow) of an engine lubricant at elevated temperatures under constant shear, simulating the narrow tolerances and high speeds between moving parts in a hot engine.
 
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Del64

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Thank you everyone. I was planning on sticking 5W30 for sure however the range open to me of ACEA A3 compared to A5 is staggering, it is roughly 5 to 50 oils, hence why I asked.

I will resume my search on A3. Thanks to all of you very much appreciated input.
 
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Thank you everyone. I was planning on sticking 5W30 for sure however the range open to me of ACEA A3 compared to A5 is staggering, it is roughly 5 to 50 oils, hence why I asked.

I will resume my search on A3. Thanks to all of you very much appreciated input.
So what about that owner’s manual, what does it suggest?

And what 5-grade oils are you finding that are ACEA Sequence A3?
 

Del64

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So what about that owner’s manual, what does it suggest?

And what 5-grade oils are you finding that are ACEA Sequence A3?
The owners manual is as simplistic as US 0W20 ACEA A3, and outside the US 5W30 again ACEA A3
I am seeing Mannol 5W30 A3, TripleQX, Total Quartz (online, Shell Helix Ultra) Valvoline SYNpower

There are a few others but these keep appearing
 
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You could walk into Halfords and purchase any oil on the shelf with a viscosity of *w20, *w30 or *w40 and run it. The car wouldn't care in our climate!

If it was mine? M1 0w40 FS or Castrol Edge 0w40 A3/B4.
 

Del64

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Aug 5, 2022
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You could walk into Halfords and purchase any oil on the shelf with a viscosity of *w20, *w30 or *w40 and run it. The car wouldn't care in our climate!

If it was mine? M1 0w40 FS or Castrol Edge 0w40 A3/B4.
Thats an interesting view I thought A3 vs A5 was a serious consideration, as my preference is the 5w30 Petronas
 
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Thats an interesting view I thought A3 vs A5 was a serious consideration, as my preference is the 5w30 Petronas

Not on your engine in our environment.

A5 is generally 'thinner' and A3 are 'thicker' more performance orientated oils.

The fact your engine recommends *w20 in the US and a *30 A3 oil in the UK shows the engine is tolerant to a wide range of viscosities.

If I worked the engine hard, then I'd go for an A3/B4 oil. If I took it easier then I'd probably look for whatever is cheaper. Whether that be a A5/B5, A4/B4, C2, C5, C3 or C4. I'd even look towards heavy duty engine oils, something that meets ACEA A6, E7 or E9 coupled with API SN.

Your engine is not fussy.
 
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