Viscosity Application question

[silversapphire]

Hi all,

I own a 1999 Mazda Miata. The owner's manual says to use 10w30 oil for most weather conditions. My question is, is there anything wrong with using a synthetic 0w30 oil? It has the same viscosity at operating temp as the 10w30, but lower viscosity @ 40C so wouldn't the 0w30 actually be the better oil to use?

Thank you

 

[tig1]

No problem using 0-30.

 

[ARCOgraphite]

Does it really have a lower KV40? Than ???

In MD, you don't need a 0W. That just about moving gel point at-or-below -40C/F Do you drive at 30 below?

Just look for the biggest VI #'s in a 30 multigrade. Maybe it is M1 AFE. I would question that though.

Now I have to look

 

[69GTX]

You have to know how much that 0w30 will shear during your OCI to compare it to the 10w30. IIRC for regular M1, their 5w30 actually starts off with a higher visc that their 10w30. And some of the 10w30 add packs might end up being significantly weaker than the 0w-30. It depends on which brand oil in most cases. Probably splitting hairs between 0w-30, 5w30, and 10w30 though. Since the 10w will likely flow fine in all Maryland temp conditions, that probably gives you the strongest film strength at startup....where both the 0w and 10w flow fine as soon as oil pressure is up.

 

[SuperSalad]

Originally Posted By: silversapphire
Hi all,

I own a 1999 Mazda Miata. The owner's manual says to use 10w30 oil for most weather conditions. My question is, is there anything wrong with using a synthetic 0w30 oil? It has the same viscosity at operating temp as the 10w30, but lower viscosity @ 40C so wouldn't the 0w30 actually be the better oil to use?

Thank you

Yes 0w30 will typically have a more steady viscosity curve from subzero to operating temperature. So it flows better at low temperatures and doesn't really have a downside other than price and availability maybe.

 

[Ohle_Manezzini]

At 40C even straight 30 is flowing well.

 

[FCD]

Basically you won't need the 0w30 unless you live somewhere where temperatures go down to -40C or F, 5w30 synthetic will serve you fine in the lower 48 99% of the time.

 

[LeakySeals]

Depends on the oil brand. The ones that know on here state M1 5w30 is actually thinner than M1 0w30 in most "cold" conditions.. until it gets Siberia cold, then M1 0w30 is thinner. But can you run 0w30? Sure, why not. There was no such thing back then, why its not in the manual. Only thing you need to worry about is consumption or leaks being an older engine. I bet you notice improved performance and MPG with less friction and better flow with a thinner oil.

 

[ndfergy]

10W30 is fine for your climate. The key is the Borderline Pumping Temperature relative to the pour point where adequate oil flow and pressure are present. This is generally 20F/11C above the pour point. Most conventionals have a PP @ -30C+ so if your experiencing winter temps frequently lower than '0' degrees fahrenheit then a lower 'W' grade is in order.

 

[ndfergy]

Originally Posted By: ndfergy
10W30 is fine for your climate. The key is the Borderline Pumping Temperature relative to the pour point where adequate oil flow and pressure are present. This is generally 20F/11C above the pour point. Most conventionals have a PP @ -30C+ so if your experiencing winter temps frequently lower than '0' degrees fahrenheit then a lower 'W' grade is in order.


Apologies leakySeals I meant to reply to the Original Poster

 

[Y_K]

Originally Posted By: ndfergy
10W30 is fine for your climate. The key is the Borderline Pumping Temperature relative to the pour point where adequate oil flow and pressure are present. This is generally 20F/11C above the pour point.

Thank you for another useful reference point

 

[CR94]

Originally Posted By: LeakySeals
... I bet you notice improved performance and MPG with less friction and better flow with a thinner oil.
I bet he won't notice "better flow" in Maryland. Maybe in Manitoba.

 

[Shannow]

How would one go about noticing either when the difference is between an ILSAC 0W30 and 10W30 ?

10 below freezing, and they will all "flow" about the same, and the difference in friction would be negligible...

 

[Garak]

Originally Posted By: silversapphire
It has the same viscosity at operating temp as the 10w30, but lower viscosity @ 40C so wouldn't the 0w30 actually be the better oil to use?

I would say yes, but some are concerned about shear stability. If that happens to be your concern, there are 0w30 A3/B4 options, for instance, that have a higher HTHS to begin with.

As for people mentioning cold starts, none of it matters unless you're at the limits, really. A 0w30 is always thinner when it matters than any 5w30, because when it matters is when you start approaching the limits of 5w-XX and 0w-XX oils, not at 5 F or something like that.

During a cold Saskatchewan winter, GC 0w30 is always more appropriate than an ILSAC 10w30, since it is quite possible to run into conditions where the 10w30 will not pump. That's not going to be a problem with the 0w-30, despite that it's going to be thicker at operating temperatures.