Do You Love Your Mazda? Ditch That 0W-20 Oil!!!

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5W-30 is fine too, as long as you don't experience cold winters:

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But I don't see the advantage. The higher the viscosity, the greater the resistance to oil flow. Generally speaking, using higher viscosity oil decreases oil flow rate and increases oil pumping losses, and so provides less oil pressure to the points of lubrication. That's particularly a concern when the engine is started cold, which is when the most engine wear occurs. Plain bearings, such as the ones that support your crankshaft and camshaft, depend on oil pressure and flow rate to maintain film thickness. Another potential downside of higher viscosity oil is that it increases friction between lubricated surfaces that are moving past each other, e.g. a crankshaft spinning in a plain bearing. That increases shearing forces within the oil, which breaks down the oil faster.
 
Red MC said:
Plain bearings, such as the ones that support your crankshaft and camshaft, depend on oil pressure and flow rate to maintain film thickness.
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Oil pressure isn't responsible for the hydrodynamic wedge that supports plain bearings. You are correct about thinner oil flowing better...
 
By the way, Liqui Moly oils do not have any moly in them, except for specialty oils. Odd, don't get fooled by the company name. They produce excellent moly additives though...
 
CX-5um said:
Questions:

Could be just Liqui Moly being better than that Castrol... and not having to do anything with weight. Maybe you should try Castrol 5w-20 to verify?

International Engine oil is spec'd differently than US spec Oil. Or is it North American spec oil?

Is US spec 0w-20 oil more similar to international 5w-20 oil than international 0w-20 oil?

Where is area 52?
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I tried castrol 5w30 once before switching to liqui moly. I noticed more of a difference switching to 5w30 then liqui moly. (the oil weight, regardless of what oil brand you use WILL make a difference) but I noticed that the castrol sheared very quickly and made the engine run noisy again after the oil became dirty. This liqui moly Stuff is so tough to fuel shear and the engine just continues to run smoothly even once the oil has become dirty (unlike what Ive tried in the past)

Its a North American thing to use 0w-20. Any 0w oil will be thinner then 5w oil, but it varies from brand to brand. For example, a poor quality 5w30 oil like Mobil 1 will provide less protection then liqui moly 0w40.

Red MC said:
5W-30 is fine too, as long as you don't experience cold winters:

cache.php


But I don't see the advantage. The higher the viscosity, the greater the resistance to oil flow. Generally speaking, using higher viscosity oil decreases oil flow rate and increases oil pumping losses, and so provides less oil pressure to the points of lubrication. That's particularly a concern when the engine is started cold, which is when the most engine wear occurs. Plain bearings, such as the ones that support your crankshaft and camshaft, depend on oil pressure and flow rate to maintain film thickness. Another potential downside of higher viscosity oil is that it increases friction between lubricated surfaces that are moving past each other, e.g. a crankshaft spinning in a plain bearing. That increases shearing forces within the oil, which breaks down the oil faster.
Click to expand...

cx-500 said:
Oil pressure isn't responsible for the hydrodynamic wedge that supports plain bearings. You are correct about thinner oil flowing better...
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Like I was saying, the engine did not struggle or seem to work any harder on cold starts. The cold starts honestly sounded healthier with LESS drivetrain clatter because of the thicker oil. Like Ive said earlier, we have been using 5w30, 5w40 and even 10w oils for ages until 0w came around for fuel efficiency benefits with zero issues. Thinner oil may flow better, but that doesnt mean you should be putting OVERLY thin oil into your car. If you live in an area with very cold winters, then you may want to consider using 0w30. But for the summers, you really should not be using anything but 5w30, especially considering that fuel shearing is a real thing (especially if you frequently drive in the city) and DI motors like ours are subjected to this even more.

yugrus said:
By the way, Liqui Moly oils do not have any moly in them, except for specialty oils. Odd, don't get fooled by the company name. They produce excellent moly additives though...
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Regardless liqui moly is top-notch Stuff. It is very good quality oil.
 
Fuel shearing? Hmm, that's new. Fuel dilution maybe? Regardless, pretty much any retail synthetic oil on WM shelf is top notch. So is Mazda's and Toyota's. I'd like to see something that proves otherwise.
 
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yugrus said:
Fuel shearing? Hmm, that's new. Fuel dilution maybe? Regardless, pretty much any retail synthetic oil on WM shelf is top notch. So is Mazda's and Toyota's. I'd like to see something that proves otherwise.
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My apologies, I meant oil shearing from fuel. Oil dilution (with fuel) is essentially the same thing and it is a real issue with lesser quality oils.

Your average oil like castrol or Mobil 1 will shear and needs to be changed Frequently. If its a 0w20 oil you can count on it for 100%.
 
GJ-Molestor said:
Like I was saying, the engine did not struggle or seem to work any harder on cold starts. The cold starts honestly sounded healthier with LESS drivetrain clatter because of the thicker oil.
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I wouldn't judge an oil's performance based on sound. Back in the 1990s, I switched over from 10W-40 to 20W-50 in a couple of my air cooled motorcycles because I noticed less valvetrain noise. But I ended up having to adjust the valve clearances more often so if anything I suspect more cam wear. And I'm not sure that what I "heard" wasn't just placebo effect anyway.

Like Ive said earlier, we have been using 5w30, 5w40 and even 10w oils for ages until 0w came around for fuel efficiency benefits with zero issues. Thinner oil may flow better, but that doesnt mean you should be putting OVERLY thin oil into your car. If you live in an area with very cold winters, then you may want to consider using 0w30. But for the summers, you really should not be using anything but 5w30, especially considering that fuel shearing is a real thing (especially if you frequently drive in the city) and DI motors like ours are subjected to this even more.
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You have a water cooled engine. Once warmed up, it runs at the same operating temperature on a cold winter day as it does on a hot summer day. 0W-30 motor oil and 5W-30 motor oil have the same viscosity in an engine that is up to normal operating temperature. The difference is in the cold viscosity. The 5W-30 oil will be more viscous when cold, which is of no benefit in hot weather but is a liability in cold weather.

The gradual transition from SAE 10W-40 to 5W-30 and now to 0W-20 over the last several decades is partially driven by fuel economy but I'm sure there's other factors. All else being equal, lower viscosity = less pumping loss = more power. And you can use smaller oil pumps. And smaller filters. And maybe even smaller oil passages too. I think that tighter manufacturing tolerances and better metallurgy is what makes it possible to use lower viscosity oils in today's engines. I know that in bearings, there is an inverse relationship between diametral clearance (i.e. the difference between shaft O.D. and bearing I.D.) and bearing load capacity. If you can maintain tighter tolerances, you can reduce the diametral clearance and support greater loads with smaller bearings, but you need lower viscosity oil to maintain the necessary flow rate of oil through the bearing.

Anyway, engines have only gotten more reliable over the years, and modern engines burn less oil than older engines. So that gives me confidence that the engineers who are specifying the oil grade know what they are doing.
 
GJ-Molestor said:
My apologies, I meant oil shearing from fuel. Oil dilution (with fuel) is essentially the same thing and it is a real issue with lesser quality oils.

Your average oil like castrol or Mobil 1 will shear and needs to be changed Frequently. If it’s a 0w20 oil you can count on it for 100%.
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I’m sure I have read worse garbage but I can’t remember when. There is nothing more than what goes off in your head to substantiate virtually all of your comments on this subject.
 
Red MC said:
I wouldn't judge an oil's performance based on sound. Back in the 1990s, I switched over from 10W-40 to 20W-50 in a couple of my air cooled motorcycles because I noticed less valvetrain noise. But I ended up having to adjust the valve clearances more often so if anything I suspect more cam wear. And I'm not sure that what I "heard" wasn't just placebo effect anyway.



You have a water cooled engine. Once warmed up, it runs at the same operating temperature on a cold winter day as it does on a hot summer day. 0W-30 motor oil and 5W-30 motor oil have the same viscosity in an engine that is up to normal operating temperature. The difference is in the cold viscosity. The 5W-30 oil will be more viscous when cold, which is of no benefit in hot weather but is a liability in cold weather.

The gradual transition from SAE 10W-40 to 5W-30 and now to 0W-20 over the last several decades is partially driven by fuel economy but I'm sure there's other factors. All else being equal, lower viscosity = less pumping loss = more power. And you can use smaller oil pumps. And smaller filters. And maybe even smaller oil passages too. I think that tighter manufacturing tolerances and better metallurgy is what makes it possible to use lower viscosity oils in today's engines. I know that in bearings, there is an inverse relationship between diametral clearance (i.e. the difference between shaft O.D. and bearing I.D.) and bearing load capacity. If you can maintain tighter tolerances, you can reduce the diametral clearance and support greater loads with smaller bearings, but you need lower viscosity oil to maintain the necessary flow rate of oil through the bearing.

Anyway, engines have only gotten more reliable over the years, and modern engines burn less oil than older engines. So that gives me confidence that the engineers who are specifying the oil grade know what they are doing.
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But never mind that engineering. Listen with your ear. Supercedes empirical data...
 
GJ-Molestor said:
My apologies, I meant oil shearing from fuel. Oil dilution (with fuel) is essentially the same thing and it is a real issue with lesser quality oils.

Your average oil like castrol or Mobil 1 will shear and needs to be changed Frequently. If it’s a 0w20 oil you can count on it for 100%.
Click to expand...
How do you know it shears that much so it has to be changed frequently? I'd like to see your data, if you don't mind.
 
Red MC said:
I wouldn't judge an oil's performance based on sound. Back in the 1990s, I switched over from 10W-40 to 20W-50 in a couple of my air cooled motorcycles because I noticed less valvetrain noise. But I ended up having to adjust the valve clearances more often so if anything I suspect more cam wear. And I'm not sure that what I "heard" wasn't just placebo effect anyway.
Click to expand...

Agreed, but I still believe that 0w20 is not enough protection. With the hood up there was tons of valvetrain clatter. With the hood up using the new oil literally all you can hear was the injectors, it sounded much healthier then before.

Like you said the sound doesnt necessarily equate to a healthier engine, but then again maybe it does? I just noticed that the engined revved a lot quieter and smoother then before, it felt far more refined.

Most importantly, oil consumption was slashed in half which is another reason why Im using this stuff.
 
If you USE oil, you're way better off with 0w20. If your oil level RAISES during OCI, then you've got to try 5w30.
 
RE oil consumption..I'm at or near 0 per 7500 @70k miles- anyone (else) have this issue?
 
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GJ-Molestor said:
Agreed, but I still believe that 0w20 is not enough protection. With the hood up there was tons of valvetrain clatter. With the hood up using the new oil literally all you can hear was the injectors, it sounded much healthier then before.

Like you said the sound doesn’t necessarily equate to a healthier engine, but then again maybe it does? I just noticed that the engined revved a lot quieter and smoother then before, it felt far more refined.

Most importantly, oil consumption was slashed in half which is another reason why I’m using this stuff.
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Important part in bold there
 
Yeah 35 miles each way to work so yeah mostly those but plenty of shorter stuff too..and maybe I've added half a qt @5k few times (to be safe) but I think those were times it wasn't quite topped up to start with..either way a half quart addition in a 7500 mile run I ain't complaining and it doesn't seem to be accelerative at all.
 
See, with short trips the level goes up, not down. Because of fuel dilution. That's the nature of the beast.
 
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