Help me understand...

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marcre

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I'm no viscosity expert. What the difference between 0w40 and 5w40? I'll save some one the trouble of the easy answer… One is 0w and the other is 5w.

I have a VW Jetta that takes the 5w40, but I am finding it tougher to find over the last year. No WM carries it around here. Last time I went to the AAP they had none. Today they had 5w40 Syntec(which is great because I like that oil), but they also had 0w40 M1. Says European, so great… I know it is for my vehicle. I'll go back tomorrow and get it since there's an oil change special on the M1 nd not the Syntec.

I guess, what I am wondering is a few things. What's the difference in the two weights? When would one be more beneficial than the other? Is there any reason to chose one over the other? Anyone prefer one weight to another?

Thanks
 
The difference between the two weights (viscosities) depends on the temperature at which they are measured. At 100C, no difference, at lower temps, the 0W flows better.

I am a big fan of the Mobil 0W40 - great choice for Euro cars...but as you can see in the sig...I am not picky...
 
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There's an indiscernible difference between the 5w-40 and 0w-40. You'd never even know it. Unless you live in the arctic circle.
 
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Originally Posted By: jeeprnovru
Rotella T6 5w40 !!!


+1

Choosing between Mobil 0w-40, Syntec 5w-40, and Rotella T6 5w-40 really comes down to cost - and T6 is almost always cheaper unless you find a great sale.
 
Thanks for the replies. I know I have the wrong stuff in there now… Only time I did it, but could not honestly find the 5w40 at the time, so I put in 5w30 Ultra. Figure it is fine for a shorter OCI.


Originally Posted By: Astro14
The difference between the two weights (viscosities) depends on the temperature at which they are measured. At 100C, no difference, at lower temps, the 0W flows better.

I am a big fan of the Mobil 0W40 - great choice for Euro cars...but as you can see in the sig...I am not picky...


Would M1 0w40 be a better choice? Or realistically, it doesn't matter as long as the VW spec is on the bottle?
 
5w-40 is reasonably pumpable down to about -25º C. 0w-40 will go down to -30º C. That's all you can tell for sure from the viscosity grade; anything else requires more detailed knowledge of the specific formulations in question.

It's possible that the 5w-40 will be more resistant to shearing, i.e. less likely to thin out over the course of an OCI. It's not certain, though. And realistically, you probably won't have to worry about that unless your engine is really hard on its oil.

It's also possible that the 0w-40 will move a little more freely on a cold start, but again, it depends on what exact oils you're talking about and probably won't matter in practice.

Mobil 1 0w-40 is a great product. It's probably one of the best you can buy on store shelves. If I had to run an off-the-shelf oil, I would take it any day of the week and twice on Sundays -- not because it's a 0w-40 per se, but because it's one of Mobil's flagship lubricants and carries nearly every major high-performance OEM approval under the sun.

I have chosen not to limit myself to store-bought products, and am currently using a 5w-40 -- again, not because of its viscosity grade, but because as far as I can tell it is the right product for other reasons that have nothing to do with its viscosity grade.

In short: unless you're looking at a viscosity grade that is way too high or way too low, make your choice based on other factors.
 
Originally Posted By: marcre
I'm no viscosity expert. What the difference between 0w40 and 5w40? I'll save some one the trouble of the easy answer… One is 0w and the other is 5w.

I have a VW Jetta that takes the 5w40, but I am finding it tougher to find over the last year. No WM carries it around here. Last time I went to the AAP they had none. Today they had 5w40 Syntec(which is great because I like that oil), but they also had 0w40 M1. Says European, so great… I know it is for my vehicle. I'll go back tomorrow and get it since there's an oil change special on the M1 nd not the Syntec.

I guess, what I am wondering is a few things. What's the difference in the two weights? When would one be more beneficial than the other? Is there any reason to chose one over the other? Anyone prefer one weight to another?

Thanks


simple answer, a 0/40 flows better at low temps
 
Better? That's pretty subjective, since we're discussing two BITOG perennial favorites...and since you're asking about 2 oils that I am currently running, it's hard for me to recommend one over the other. The T6 is good stuff, but realistically, you're OK either way...and you're OK with a 5W40 in the DC area...that T-6 will be fine for any temp you could ever encounter, even if you went to Canada for the weekend...in January...

What can you get on sale?
 
Originally Posted By: jeeprnovru
Rotella T6 5w40 !!!


Are you on VWVortex?


I think so, haven't been there in a long time though.
 
Originally Posted By: Astro14
Better? That's pretty subjective, since we're discussing two BITOG perennial favorites...and since you're asking about 2 oils that I am currently running, it's hard for me to recommend one over the other. The T6 is good stuff, but realistically, you're OK either way...and you're OK with a 5W40 in the DC area...that T-6 will be fine for any temp you could ever encounter, even if you went to Canada for the weekend...in January...

What can you get on sale?


On sale is the deciding factor. At the AAP I go to they have two choices… M! 0w40 and Syntec 5w40. I have always been a fan of syntec and I know M1 is good, so I'll use either. M1 is cheeper this month I believe, so I guess I'll try that. Even though I won't change the oil for a couple weeks.
 
Originally Posted By: JRed
Choosing between Mobil 0w-40, Syntec 5w-40, and Rotella T6 5w-40 really comes down to cost

Mobil 1 0w-40 carries no real diesel/HD approvals but tons of high-performance gasoline approvals. Rotella T6 5w-40 is completely the opposite. Syntec 5w-40 is outdated. I don't see how those three can be compared, let alone how cost can be the main determining factor.
 
Sounds like a plan!
cheers3.gif
 
Originally Posted By: jeeprnovru
if this is a turbo jetta id pick the T6 over the M1

Why is that?
 
Originally Posted By: jeeprnovru
if this is a turbo jetta id pick the T6 over the M1


It's not turbo…

For me it's between the Castrol and M1. Only because those seem to be the only two I see on the shelves.

I've used the Castrol before, not the M1, but I know they are both good.

Was really just curious about the differences between the two weights(0w40 and 5w40.
 
The W-number in an oil's viscosity rating refers to the maximum allowable viscosity that it has when measured in a standardized test. API specifications have the following requirements:

0w: 6200 centipoise @ -35C in the Cold Cranking Simulator
5w: 6600 cP @ -30C
10w: 7000 cP @ -25C
15w: 7000 cP @ -20C
20w: 9500 cP @ -15C

The lower viscosity of the 0w oil, means that the cranking system does not have to work as hard to turn the engine over in sub-freezing temperatures, and that the oil will flow more quickly to all parts of the engine after starting. If you're in the Washington DC area, a 5w-40 would work OK. Although if you would ask me to choose between M1 0w40 and Syntec 5w40, I would go with Mobil 1.
 
Thanks for the info.


I'm probably going to check out the M1. Seems like many like it.

Originally Posted By: A_Harman
The W-number in an oil's viscosity rating refers to the maximum allowable viscosity that it has when measured in a standardized test. API specifications have the following requirements:

0w: 6200 centipoise @ -35C in the Cold Cranking Simulator
5w: 6600 cP @ -30C
10w: 7000 cP @ -25C
15w: 7000 cP @ -20C
20w: 9500 cP @ -15C

The lower viscosity of the 0w oil, means that the cranking system does not have to work as hard to turn the engine over in sub-freezing temperatures, and that the oil will flow more quickly to all parts of the engine after starting. If you're in the Washington DC area, a 5w-40 would work OK. Although if you would ask me to choose between M1 0w40 and Syntec 5w40, I would go with Mobil 1.
 
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