Mazda3 Forums banner
1 - 20 of 24 Posts

·
Registered
Joined
·
658 Posts
Discussion Starter · #1 ·
This came up in another thread and I'm interested in more info about this. And I apologize if there's already a thorough discussion about this elsewhere that I missed.

I understand, roughly (and basically), that 5W-20 offers ever-so-slightly better MPG, while 5W-30 may offer slightly better engine protection. The owner's manual recommends 5W-20, but if I understood correctly from the other thread, in other countries the spec for the non-turbo 3 is 5W-30. Is this true?

Basically, I just want to know which is best to use. I know there's probably not a huge difference between the two, but for how important oil is to the longevity of the car, I want to be sure I have it right. What are the reasons for switching from 5W-20 to 5W-30? And is it true that in other countries the spec for this engine is 5W-30?

Appreciate any and all insight. If it's worth anything, I'll be switching to synthetic soon as well. And no I don't need a lecture on that, I fully aware of the discussions that have gone on about that. :)

Edit: Oh yeah, and if possible, please provide sources (or something) if possible.
 

·
Registered
Joined
·
151 Posts
Re: 2.0 Engine: 5W-20 vs. 5W-30

There is hardly any difference between the 2.0 and the 2.3 That .3 difference is distributed among 4 cylinders and is only a difference in the "stroke" of the engine, not piston size. The 2.3 gets a slightly longer stroke on its pistons travel length. The difference between 5w20 and 5w30 is small as well. But I firmly believe that a 5w30 is a better spec'd oil and my engine (2.3) is smoother and quieter with it. At full operating temp the 5w30 provides better protection and a longer oil change interval as well. After approx 5000 miles the 5w30 properties will have sheared down to a 5w20 anyway. A 5w20 will shear down to a 5w10-15 at best. Not the kind of protection I want.
 

·
Registered
Joined
·
658 Posts
Discussion Starter · #3 ·
Re: 2.0 Engine: 5W-20 vs. 5W-30

I understand the differences are small, but doesn't the owner's manual recommend 5W-30 for the 2.3? That's why I'm asking specifically about the 2.0s--not just because I own one, but because the manuals specifically states to use 5W-20 in them. I could be wrong though--maybe it's just the Speed3s that have the 5W-30 spec. Appreciate the thoughts either way, though.

Also, does anybody know if there's any warranty concerns with this (switching from 5W-20 to 5W-30)?
 

·
Registered
Joined
·
3,493 Posts
Re: 2.0 Engine: 5W-20 vs. 5W-30

[quote author=Chaos link=topic=137189.msg2957180#msg2957180 date=1235445245]
maybe it's just the Speed3s that have the 5W-30 spec. Appreciate the thoughts either way, though.
[/quote]

That is correct, 5w20 is recommended for both the non-turbo 2.0 and 2.3 engines. Only the DISI 2.3 is recommended to use 5w30.

I can tell you that I've been running Mobil 1 5w20 in my car since it was brand new, and even with 40,000 miles on it now, every UOA I've sent back has come back looking great. I usually run my oil 5,000 miles between changes. Don't run an oil too long, and you won't really need to worry about shear too much...IMHO of course, there will be plenty of people here who think I'm stupid. :p
 

·
Registered
Joined
·
658 Posts
Discussion Starter · #5 ·
Edited the thread and the thread title, thanks for the heads up.
 

·
Registered
Joined
·
2,321 Posts
I'm at 55K miles and I've been running Pennzoil Platinum 5w20 for the last 40K. The one UOA I received after a 7500K mile run on 5w20, came back flawless. In fact, the lab suggested that I could have even run it longer. Use 5w20 with confidence!!!
 

·
Registered
Joined
·
253 Posts
5w30 made my 2.3 a lot quieter. I use pennzoil platinum by the way, with purolator pureone air and oil filters. Im running 10,000 mile change intervals also with great success. I did a UOA at 7500 miles and they said I could go to 10,000 with no problems. I drive 100 miles a day mostly on the interstate and I got tired of changing my oil every month.

I tried 5w20 M1 awhile back but it didn't make the engine any quieter than regular oil.

I rec. PP 5w30 with purolator air/oil filters for anyone. Its a great combo!
 

·
Registered
Joined
·
2,321 Posts
stranger - Have you tried PP in the 20-weight formula? I'd be interested to compare a UOA of that vs. the PP 5w30 in your engine. Either will obviously work, but it would be interesting to hear if one performs a little better.
 

·
Registered
Joined
·
253 Posts
No I haven't...I'd rather not go back to 20 weight. In my opinion its just too thin for my driving conditions. Especially since Im down in southern alabama where we see 100+ during the summer months along with 95% humidity year-round. That and by the time I hit 10,000 miles on the oil, its pretty much sheared down to a 20 weight. My car seems to love 30 weight. Its definitely a lot quieter and Im pretty sure it runs smoother. I haven't noticed any difference in fuel economy. Still averaging just over 30 mpg as always.
 

·
Registered
Joined
·
2,321 Posts
I understand your hesitation. I've read on BITOG (BobIsTheOilGuy.com) numerous times about Mobil1 creating more noise in general, so that's why I think it'd be interesting to compare PP 5w20 with PP 5w30. Either way, Platinum is a great oil so it's all good.

:)
 

·
Registered
Joined
·
6,863 Posts
i am using 5w-30. 5w-20 just doesn't seem right to me and i drive my car hard a lot.
 

·
Registered
Joined
·
2,321 Posts
[quote author=stranger706 link=topic=137189.msg2959136#msg2959136 date=1235522709]
Hahaha I used to be diehard Mobil 1...BITOG completely brainwashed me!
[/quote]

LOL, you and me both man!
 

·
Registered
Joined
·
2,027 Posts
i run mobil 1 5w30 because its hot all the time here
 

·
Registered
Joined
·
658 Posts
Discussion Starter · #15 ·
So am I understanding correctly that in warmer weather, 5W-30 is better? Now I have a whole new set of questions. Is it reasonable to run 5W-20 in the colder months and 5W-30 in the warmer months, or is it not a good idea to switch back and forth like that? And if you were going to be traveling all around the country, would it be better to run with 5W-30, due to the varying climates and temperatures? Am I over-thinking this? :)
 

·
Registered
Joined
·
253 Posts
[quote author=Chaos link=topic=137189.msg2959387#msg2959387 date=1235528638]
So am I understanding correctly that in warmer weather, 5W-30 is better? Now I have a whole new set of questions. Is it reasonable to run 5W-20 in the colder months and 5W-30 in the warmer months, or is it not a good idea to switch back and forth like that? And if you were going to be traveling all around the country, would it be better to run with 5W-30, due to the varying climates and temperatures? Am I over-thinking this? :)
[/quote]

To your first question, I'll just say that my 3 does run better with 5w30. I can't speak for everyone.

Now you could switch back and forth between seasons for peace of mind, but it seems kind of a hassle and 5w30 is a great year-round weight to run, even in cold climates. Because at cold start up temps (any season), a 5w20 and 5w30 have the same viscosity. A 20 weight is simply thinner at operating temp than a 30 weight.

The only benefit to running a 20 weight is (in my opinion) a negligible gain in fuel economy.
 

·
Registered
Joined
·
151 Posts
I too use 5w30 and it in fact does make the engine quieter. But let me clear something up. In regards to outdoor temps, the vehicle doesn't know its extremely hot out, nor does it feel "wind chill" the way humans do. Icy cold winter starts are the only thing to be concerned with.
Remember, the engine gets very hot regardless of outdoor temps. And it has a thermostat built into the cooling system to make sure that it stays at a constant temp year round. Since its temps reach higher then the human body could possible live in, don't be too concerned with that. Its designed to take the heat.
With the exception of a cooling system failure, the outdoor temps don't really matter.
 

·
Registered
Joined
·
3,493 Posts
[quote author=bustednutz link=topic=137189.msg2964354#msg2964354 date=1235705340]With the exception of a cooling system failure, the outdoor temps don't really matter.
[/quote]

That's true, but only when the engine is running and at operating temp. The concern is when you start the engine -- for a few seconds, there is no oil flow (as the oil pump hasn't gotten up to pressure), so the viscosity of your oil at low temperatures can matter, as a thinner oil will flow more quickly than a thicker one. Quicker flow = getting engine parts lubricated during starting faster.
 

·
Registered
Joined
·
2,816 Posts
Actually, oil temp and coolant temp are not linear in their temperatures. I guarantee, on a 110f summer drive to Vegas, your oil temp will be much hotter then that same drive on a 40f day. Also, rpm's and load are huge factors on oil temps as well, regardless of the ambient temp.

My opinion on the 5w-30 vs 5w-20 question is this. Most, if not all, conventional 5w-30's will shear down to the SAE rating for a 5w-20 in as little as 3K miles. That's not a rumor, but a fact. Hell, a lot of "full synthetics" shear down as well, they just take a little longer to do so. So, at the end of a 5w-30 OCI, the oil is now at a 5w-20 viscosity, and most people don't have a clue.

I live in the high desert of SoCal, where we see 8f in the winter, and 113f in the summer. Summers are particularly brutal, and they probably average over 105f, from July 1st-Oct 1st. I run 5w-20 in my wife's Accord, as well as my 3. I do run a 40wt oil in the summer for my Dakota R/T that is spec'd for a 10w-30, but only because it uses quite a bit of oil.

There are literally hundreds and hundreds of UOA's on BITOG, that prove 5w-20 oils protect just as well as a heavier oil................Not a rumor, but a fact!

In the end, use what viscosity you want..................Your car will never notice the difference. :p


Darryl
 
1 - 20 of 24 Posts
Top