5w30 or 5w20?

[gookluck2010]

I know this must have been discussed somewhere but I just didn't find it.

As a new owner of a 2006 Mazda 3 hatchback (actually a first time owner of a Mazda), I am a bit confused about the engine oil.

The user manual suggests to use 5w20 engine oil. But a lot of people recommend to go with 5w30 because they think a bit thicker oil can provide better protection for the engine.

I am about to do an oil change soon. Could you guys please give me some ideas?

Thanks!

[JonsMazda]

http://www.torontomazda3.ca/forum/showthread.php?28909-5W20-Engine-Oil&highlight=engine+oil

[aris]

I run 5w30..

[gookluck2010]

I run 5w30..

Thanks aris. do you run Synthetic?

[JonsMazda]

I run 5w30 Mobil 1 full synthetic

[aris]

Thanks aris. do you run Synthetic?

Yep i run synthetic..i change mine every 12,000km

But if your still under warranty then you might still want to change every 8,000km

[gookluck2010]

I bought it as a used one. I have no idea what oil has been used on this car. Will it be a good idea to use Mobile 1 full synthetic 5w30 starting from now?


Yep i run synthetic..i change mine every 12,000km

But if your still under warranty then you might still want to change every 8,000km

[aris]

I bought it as a used one. I have no idea what oil has been used on this car. Will it be a good idea to use Mobile 1 full synthetic 5w30 starting from now?

Ya you can start now...but personaly i don't like mobile 1... I use castrol syntec...every once in a while canadian tire put's a sale on for $25 for a 4.4lL jug..when they do that i just stock up with oil..lol

[gookluck2010]

Thank you guys! I still have one year powertrain warranty left. I was wondering if using 5w-30 instead of manual suggested 5w-20 will ruin the warranty?

[Kinn]

When my motor blew in my 06 GT I recall the technician talking about oil and how the tolerances in the motor are so small that you needed to run a thin oil to ensure proper penetration between parts. I honestly have no idea if he was right or just blowing smoke. Maybe someone more knowledgeable can comment?

[aris]

When my motor blew in my 06 GT I recall the technician talking about oil and how the tolerances in the motor are so small that you needed to run a thin oil to ensure proper penetration between parts. I honestly have no idea if he was right or just blowing smoke. Maybe someone more knowledgeable can comment?

The technician that told you that was blowing smoke up your a#$.....

[stock3]

The technician that told you that was blowing smoke up your a#$.....

For sure, I just laugh at people who say that the new engines have tighter tolerances and therefore you need thin oil. They think they sound technical so that they know what they're talking about.

While it is true that tolerances are tighter because they can be better controlled due to CAD designs and computer controlled machining, but tolerances have absolutely nothing to do with oil choice, it's the clearances between parts, and frankly, clearances stayed relatively the same over the last few decades. Because you cannot change metallurgy, and metal expansion, so these design practices hold true today just the same as 30 years ago.

[g_tsb]

i ran both 5w 20 and 30, i find that with 30, i was able to bring my rpms higher a bit faster, mazda 3s like to really push out at 3000 rpms.. and the 5w30 brought it to the 3000 rpms a bit faster.. but with the 5w20 the 3000rpms pushes alot harder

[kckev99]

I've heard from a mechanic that some manufacturers have opted for 5w20 in order to get better fuel economy ratings for newer cars. He stated an example where a certain model year for a Honda Civic used 5W30 and the next model year they used 5W20. Both model years using same engine. He had contacted Honda "tech line" to inquire about the clearances and tolerances of the engines of the two different model years. He found that there was no difference between the two. He attributed the difference in using a lighter weight oil as a marketing ploy to sell the same car with better fuel efficiency in the later years. He recommended his customers to stick to 5W30 for better protection.

[mazda lover]

Ihave a 2010 Ford Edge and in the manual it says "To protect your engine and "engine's warranty" use Motorcraft SAE 5W20 or equivalent meeting Ford specification WSS-M2C930-A. SAE 5W20 oil provides optimum fuel economy and durability performance meeting all requirements for your vehicle's engine" In this case it appears if anything but 5W20 is used and an engine problem occurs the warranty might or will be void. In my Mazda's manual no mention if other than 5W20 is used it would void the warranty. Is Ford doing this to make sure owners bring their car only to a Ford dealer?
2005 M3 GT GFX Auto
2010 Ford Edge SEL FWD

[htc***]

I think 5W20 or 0W20 have a specification of WSS-M2C930-A and 5W30 or 0W30 have a specification of WSS-M2C929-A.

[Gen1GT]

5W20 is recommended for fuel economy reasons. Any other reason you hear is bull-dooty. The bearing clearances for the 2.3 litre are 0.7 to 1.1 thousandths of an inch (to a max of 3.9 thou). Even 5W40 can provide full boundry lubrication down to 5 microns in properly machined components.

I've never heard of so many blown engines than I have with people driving these engines; am I'm supposed to believe that 5W20 is somehow adequate?

[kckev99]

I know some of the guys that hit the track tend to use a heavier weight oil. Motul 5W40 and seems to withstand the excessive heat and torture. If it's good for the track I don't see why it won't offer more protection for everyday driving.

I would have to tend to agree that 5W20 is probably just purely for manufacturers to advertise better fuel economy stats. Probably offers less protection when it comes down to harsh hot conditions. Then again I have no objective proof but just my opinion.

[mazda lover]

Ihave a 2010 Ford Edge and in the manual it says "To protect your engine and "engine's warranty" use Motorcraft SAE 5W20 or equivalent meeting Ford specification WSS-M2C930-A. SAE 5W20 oil provides optimum fuel economy and durability performance meeting all requirements for your vehicle's engine" In this case it appears if anything but 5W20 is used and an engine problem occurs the warranty might or will be void. In my Mazda's manual no mention if other than 5W20 is used it would void the warranty. Is Ford doing this to make sure owners bring their car only to a Ford dealer?
2005 M3 GT GFX Auto
2010 Ford Edge SEL FWD

My oil filler cap on the Ford says 5W20 RECOMMENDED
No where does it say required or necessary,

[Frenchmanremy]

My oil filler cap on the Ford says 5W20 RECOMMENDED
No where does it say required or necessary,

The ford warranty does not cover the engine if the oil filter is not a Motorcraft. I used to work for ford, and so many people got screwed with FRAM filters, or anything else other then Motorcraft.

[Elusivellama]

Switching to 5W-30 after my BSD kit arrives and I get Jimmy to install it for me. Going with Pennzoil yellow bottle stuff.

[Gen1GT]

The ford warranty does not cover the engine if the oil filter is not a Motorcraft. I used to work for ford, and so many people got screwed with FRAM filters, or anything else other then Motorcraft.

That would be easy to challenge in court. Does that mean a Focus 2.3 can't use a filter from a Mazda3 2.3?

[htc***]

The ford warranty does not cover the engine if the oil filter is not a Motorcraft. I used to work for ford, and so many people got screwed with FRAM filters, or anything else other then Motorcraft.

That dealership try to give you a BS. This is the first time I hear about that.

[pinoy_eh]

Most often, I use full synthetic oil of different viscosities per season. During the warm to hot months (May to October), I use a 10w30, during the cold months (November till April), I use a 5w20. I have not experienced any engine issues when switching motor oil weight. Before I switch to a 10w30, I just do an engine flush.

[Rob23]

That would be easy to challenge in court. Does that mean a Focus 2.3 can't use a filter from a Mazda3 2.3?

i thought it was the europ ford focus that has the same engines, the focus here doesn't have the same 2.3 does it?

[TheMAN]

Most often, I use full synthetic oil of different viscosities per season. During the warm to hot months (May to October), I use a 10w30, during the cold months (November till April), I use a 5w20. I have not experienced any engine issues when switching motor oil weight. Before I switch to a 10w30, I just do an engine flush.
that's totally unnecessary and a waste of your time/money... just get ONE oil and stick with it... a 5W30 or a 0W30 will do you fine ALL year.... the engine is going to run the same temperatures no matter what once it's warmed up.... that's what the thermostat is for... a 5W20 oil and a 5W30 oil both have the same viscosity when the engine is cold... the only thing running 20 weight oil does in winter is offer less protection for your engine after it is warmed up...

go find out what the viscosity numbers mean and you'll understand what I'm saying

[chubbiez]

Last week i had an oil change done they put in 5w20, i'm not liking the oil, i find my 3 is smelling like oil when i accelerate and that never happend before!

[mazda lover]

that's totally unnecessary and a waste of your time/money... just get ONE oil and stick with it... a 5W30 or a 0W30 will do you fine ALL year.... the engine is going to run the same temperatures no matter what once it's warmed up.... that's what the thermostat is for... a 5W20 oil and a 5W30 oil both have the same viscosity when the engine is cold... the only thing running 20 weight oil does in winter is offer less protection for your engine after it is warmed up...

go find out what the viscosity numbers mean and you'll understand what I'm saying

Maybe this link should be a sticky. Its called Oil 101 interesting reading and very long, 10 chapters?

http://www.bobistheoilguy.com/cms/index.php?option=com_content&view=article&id=83

[TheMAN]

take it only with a grain of salt... written by a doctor and not a chemist!

[mazda lover]

take it only with a grain of salt... written by a doctor and not a chemist!

Maybe Dr Haas is a Chemist, just a thought..but you bring up a good point.

some background on Dr Haas
http://www.ozdat.com/content/index.php/Tech/Motor_Oil

[koorick]

Ya you can start now...but personaly i don't like mobile 1... I use castrol syntec...every once in a while canadian tire put's a sale on for $25 for a 4.4lL jug..when they do that i just stock up with oil..lol

How much oil could you really stock up??? I mean...dont' they have some sorta shell life on them?? like best before date??

[aris]

How much oil could you really stock up??? I mean...dont' they have some sorta shell life on them?? like best before date??

No oil does not have a shell life it's not food....

I get about 4 to 5 jugs of castrol syntec 5w30 4.4L which lasts me about a year

[TheMAN]

as long as you don't keep it in extreme temperatures, it will be fine

[mazda lover]

as long as you don't keep it in extreme temperatures, it will be fine

is keeping it in the garage ok? extreme heat and cold, or in the basement of the house?

[TheMAN]

of course not! I said extreme temperatures and there's plenty of that in the garage which is an uncontrolled environment
keeping it in the basement is fine and far better

[Gen1GT]

If the oil is un-opened, it's fine the garage. It needs air exposure to oxidate and absorb moisture, which is how most oil degrades over time.

[TheMAN]

oil bottles aren't vacuum sealed, there's air "exposure" inside the bottle

[Gen1GT]

Yeah, but you might have 50cc worth of air volume compared to 4000 cc of oil. That 50cc will give up its free oxygen pretty quickly and only have a minor effect on the oil. I'll wager the air volume in the oil container is pretty "dry air" too.

[TheMAN]

regardless, the redline oil cases I have says "store away from heat"... got to be a good reason for that... so why not just be on the safe side and store it inside the house (basement)? the basement is the extra space for random crap anyway, for most people's homes

[Gen1GT]

For sure...I'm not saying keeping it in the basement isn't a good idea. But the temperatures they're talking about are 140 degrees F and higher, because oxidation doubles every 10 degrees above that.

[stock3]

I think the "keep away from heat" warning is for the plastic bottle, so that it won't get damaged, and not for the oil itself. I mean motor oil has to endure far greater temp. swings in the engine that it can ever experience in a basement or the garage.

Also, oil doesn't oxidize and will not really absorb moisture, although moisture can condensate on the bottle and end up in oil that way, but oil will not absorb moisture from air like brake fluid does. It's the combustion byproducts and fuel dilution that create acids and degrade oil’s add pack. So as long as the container is capped, to prevent foreign objects from entering the bottle, like dirt, dust, water condensation, etc. even if it was opened before, the oil will be fine.

Just think about it, if the oil can sit in the crankcase, endure engine operation, fuel dilution, high engine temperatures and combustion byproduct and still be good for 4 - 6 months (usual OEM timer frame) and most synthetics are good for up to 12 month operation, then it can surely sit a lot longer in a capped bottle, doesn't matter it that bottle is in the garage or the basement, it will be fine.

[RECREATIONAL_ANXIETY]

I think the "keep away from heat" warning is for the plastic bottle, so that it won't get damaged, and not for the oil itself.

+1. Nothing would suck more than to have a plastic 5L jug of oil deform and leak out it's contents if you left it too close to a heat source!

[Gen1GT]

I think the "keep away from heat" warning is for the plastic bottle, so that it won't get damaged, and not for the oil itself. I mean motor oil has to endure far greater temp. swings in the engine that it can ever experience in a basement or the garage.

Also, oil doesn't oxidize and will not really absorb moisture, although moisture can condensate on the bottle and end up in oil that way, but oil will not absorb moisture from air like brake fluid does. It's the combustion byproducts and fuel dilution that create acids and degrade oil’s add pack. So as long as the container is capped, to prevent foreign objects from entering the bottle, like dirt, dust, water condensation, etc. even if it was opened before, the oil will be fine.

Just think about it, if the oil can sit in the crankcase, endure engine operation, fuel dilution, high engine temperatures and combustion byproduct and still be good for 4 - 6 months (usual OEM timer frame) and most synthetics are good for up to 12 month operation, then it can surely sit a lot longer in a capped bottle, doesn't matter it that bottle is in the garage or the basement, it will be fine.

I agree with most of what you say, but you should research oil oxidation and its hygroscopic properties. EVERYTHING oxidizes, and oil most definitely absorbs moisture. It's not as much an issue in your engine as it is in your brake system, because a braking system can easily boil the water in the fluid. Once boiled, the water is in vapour form, and changes the bulk modulus of the brake fluid (it compresses more).