0w20 or 5w20

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Agree; It's hot most of the time, and 5W is plenty thin for our NTX climate "cold starts". 5w-30 synthetic in all my vehicles for 20 yrs, except the clapped out Ranger, which runs 20w-50.
Yes. The low side of the temperature range listed in Mazda’s international owner’s manual (again, see post #15) is -25°F on 5W-30 oil and -35°F on 0W-20. Not many times in history it has reached that low at -25°F in North Texas.
 
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18 Mazda CX5 AW
I know most people won't agree with me but the lower oil viscosities are for the good of the CAFE numbers, not for the good of the engines. Will a 0w-20 get your engine way past your 36,000 warranty period? Absolutely. Gunna see 200,000 ?? Maybe. My brothers 2017 F150 5 liter V8 says 5w-20 on the cap. Not me. I live in a VERY cold place and every vehical I own gets 5w-30 full synthetic every 6000 miles, all 12 months. I own cars/trucks from 1986 to 2022. And they are very happy! :). (Kirkland SP 5w-30 actually). And for the love of God don't use FRAM oil filters. Haha
Yep.

The thing you have to remember is the engine is an expensive piece of highly tuned machinery . So why risk it? There are alot of factors that come into play including pressure and temperature. Will the thicker oils lubricate and protect the bearings and engine better. Sure will ...but only the sections it can get too. Cold weather and tight tolerances may mean no oil where needed. The thicker oils will not flow as freely through the oil pump until warm. Thus no oil during startup when needed.Add in the fact that the engine coolant cools not only the engine but also keeps the oil from super-heating. Im not a scientist but i would think thicker oils would be harder and take longer to cool off. As the mazda engines are high compression that means the engines create alot of heat. Which is bot getting dissipated as fast/easily.

It is complex and there are alot of interworking part's. So why Messi with it? Except using thicker oils on an already worn out, old engine thats ni it worth alot, why screw with the engineers design?
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
I know most people won't agree with me but the lower oil viscosities are for the good of the CAFE numbers, not for the good of the engines. Will a 0w-20 get your engine way past your 36,000 warranty period? Absolutely. Gunna see 200,000 ?? Maybe. My brothers 2017 F150 5 liter V8 says 5w-20 on the cap. Not me. I live in a VERY cold place and every vehical I own gets 5w-30 full synthetic every 6000 miles, all 12 months. I own cars/trucks from 1986 to 2022. And they are very happy! :). (Kirkland SP 5w-30 actually). And for the love of God don't use FRAM oil filters. Haha
On the contrary, many including me believe the low viscosity oils such as 0W-20 are only good for CAFE numbers. The added timing chain protection feature on newer GF-6 oil standard is due to the lack of it from older thinner oils.
 
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18 Mazda CX5 AW
Yes. The low side of the temperature range listed in Mazda’s international owner’s manual (again, see post #15) is -25°F on 5W-30 oil and -35°F on 0W-20. Not many times in history it has reached that low at -25°F in North Texas.
But you cant just take low points. We still get -10 F where we live. The question is what is the viscosity of the 5W-30 be at - 10F versus the viscosity of 0W-20 at -10 F ? At - 10F, the 0w-20 will flow more freely. And while i dont know the exact viscosities, ive seen the 5w-30 takes alot longer to pour versus 0w-20 in very cold temps
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Yep.

The thing you have to remember is the engine is an expensive piece of highly tuned machinery . So why risk it? There are alot of factors that come into play including pressure and temperature. Will the thicker oils lubricate and protect the bearings and engine better. Sure will ...but only the sections it can get too. Cold weather and tight tolerances may mean no oil where needed. The thicker oils will not flow as freely through the oil pump until warm. Thus no oil during startup when needed.Add in the fact that the engine coolant cools not only the engine but also keeps the oil from super-heating. Im not a scientist but i would think thicker oils would be harder and take longer to cool off. As the mazda engines are high compression that means the engines create alot of heat. Which is bot getting dissipated as fast/easily.

It is complex and there are alot of interworking part's. So why Messi with it? Except using thicker oils on an already worn out, old engine thats ni it worth alot, why screw with the engineers design?
But we’re talking about “thicker” 5W-30 oil which is recommended by Mazda for its SkyActiv-G engines used worldwide.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
But you cant just take low points. We still get -10 F where we live. The question is what is the viscosity of the 5W-30 be at - 10F versus the viscosity of 0W-20 at -10 F ? At - 10F, the 0w-20 will flow more freely. And while i dont know the exact viscosities, ive seen the 5w-30 takes alot longer to pour versus 0w-20 in very cold temps
As long as the oil with the said viscosity is approved by the SAE which can be used at -10°F, we shouldn’t be worried about it.

Besides, the protection is only for a very short period of time during the initial start-up in very cold temperature. For mostly very hot weather in Texas, high temperature protection is more important to the engine. Most likely 5W-30 oil protects engine better than 0W-30 in such conditions.
 
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18 Mazda CX5 AW
As long as the oil with the said viscosity is approved by the SAE which can be used at -10°F, we shouldn’t be worried about it.
Also though, if 5w-30 raises fuel consumption thus their is more gasoline combustion, thus more heat and pressure thus more engine wear...

Now to those that trade in cars every few years, they may not care.

But I run mine til the frames rust out. Until myth-busters does a segment on engine wear, i think ill stick with the engineers specs, even after the warranty period.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
⋯ But I run mine til the frames rust out. Until myth-busters does a segment on engine wear, i think ill stick with the engineers specs, even after the warranty period.
Yeah, and Mazda engineers said 5W-30 oil can also be used in our SkyActiv-G engines, period. (Again, see post #15)
 

madar

Contributor
:
2016.5 CX 5 Touring AWD, 2015 SCION XB
I'll be switching to 0W-30 after winter. 63K miles on our 2014 CX-5 GT & I noticed the engine is a little louder. Not clattering, just not as quiet. Also it uses 3/4 quarts every 5K miles now so tolerances probably aren't as tight as new. I wouldn't use 0W-30 when new but now it shouldn't be a problem. Especially with our 110 degree Texas summers. I like Amsoil full synthetic.
Different oil formulations give different results. I was a diehard PP user for years, both on my current CX5 and my '14 model. I was using a quart of oil every 4k miles. I do a lot of hard driving. I experimented with Ravenol 0w-20 oil just to see if was an engine issue or oil. Ravenol is mostly a PAO oil (a true synthetic oil, and quite expensive being imported from Germany) for a year and was using almost a quart at 6500 miles. It's a fantastic oil and the engine was very quiet running. Now I'm using Mobile 1 EP 0w-20, which is about 30% PAO, up to 600 miles on this change and no oil consumption yet. GDI engines are tough on oil. I'm still bound to an extended warranty so I'm sticking with 0w-20 for now. I always believed 0w-20 was crap.
 
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BMW M3 / Mazda5
Yes, the push for xW-20 oils (and thinner) has been for fuel economy reasons. That doesn't mean it's bad for protection. It's complicated.

xW-30 might retain thicker films in the highest-temp, highest-shear areas of the engine. xW-20 will reduce wear before the engine gets up to temp, which is when many of us will be causing most of our engine wear. What's the net effect? None of us here has any idea one way or the other. It will vary from case to case based on variables most of us can't even comprehend let alone figure out.

Plus, if you buy an xW-20 oil that meets modern specs, there's actually more of a guarantee of high quality base stocks than if you buy an xW-30 that meets the same specs. The lower the viscosity grade, the higher the base stock quality "floor" to prevent it from cooking off too easily. Again, what's the net effect for either viscosity grade? Impossible for us to say.

You know who knows? Mazda. What's the probability they'll share what they know? Zero.

All we can say for sure is that any oil that meets the manufacturer's specs will work well enough that it probably won't be the liming factor on engine life. Isn't that what we're all trying to achieve?
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
⋯ All we can say for sure is that any oil that meets the manufacturer's specs will work well enough that it probably won't be the liming factor on engine life. Isn't that what we're all trying to achieve?
Yes. And the discussion started with when the engine is consuming oil and is getting noisier, use Mazda (also) recommended 5W-30 oil on the 2.5L NA could help the situation.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Different oil formulations give different results.
Most definitely. Different brand of oil with the same viscosity may have different result on oil consumption. When I was with VW Passat forum people swore that the hard to find made in Germany Castrol Syntec 5W-30 oil has much better “performance” and much less oil consumption for the 2.8L V6 than the made in USA Castrol Syntec 5W-30 oil which was widely available although the packages were looked the same other than the country of origin.
 

Kedis82ZE8

'12 GX 460,'07 G35x / '15 CX-5 AWD GT w/Tech Pkg
Contributor
Toyota has been using 0W-20 for like a decade or so and have been using in my GX for years. No issues...

So far the Mazda moly 0W-20 which I have used since new has kept oil consumption to "not noticeable"

I will continue to use it in those vehicles... only auto I deviate is the '07 G35x.... still using the specified 5W-30 and no noticeable oil consumption there either.

Alway used the Mazda moly in the CX-5 and Amsoil in the other rigs.
 

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