0W vs 5W - benifical differences ?

[chefwong]

Is there any substantial difference running 0W vs 5W, bearing the 0W will flow better upon intial start up ?

I've got some bottle of GC and Redline 5W30. Winter out here in NYC averages around 28F. Will I see any real world benefical differences by running a thinner oil ?

The oil in my car (brand new) was changed out at 3200 miles and I'm planning to do another soon. It was changed out with Redline 5W30 and I was planning to do another change with Redline and then get start a UOA off that change, come spring.

I may go with GC if it will *benefit* my engine since it will flow better in the winter.

Love to get some oil gurus feedback or opinion on this.

 

[quadrun1]

At 28F, I don't think there's much advantage in using a "0W" over a "5W" oil. But since you have it, why not try it?

In a week or two, I will be installing GC into my SAAB turbo.

So you found some GC in Brooklyn?

 

[chefwong]

Actually, I looked for some back when AZ was running the Castrol special. Picked up 2 cases in the AZ out in the city, right off Houston Street. An oil change for me takes up 8.5q so I got enough for 3 changes.

 

[williar]

I disagree with quadrun1; I say the lighter the winter weight number the better, even in the summertime. For the first few miles, the lighter number should provide less engine wear and better fuel economy. It's all gain with no downside.

Of course, the oil must protect on the high side, too, with proper viscosity, HT/HS, and so forth.

 

[JohnBrowning]

You will not see a difference! The Army's artic oil is a synthetic 5W30. While the military does not always have the best products rest assured that they have tested exhaustively to determine that their artic spec. will perform.

On a side note Terry informed us that Amsoil's 5W30 is almost spot on for the Army's artic spec. oil.

Either oil will work just fine. I am partial to Redline. I am going to have to see more results from GC. It would also help if I caould find some to try. So far Castrols distribution of GC has been pathetic!!

 

[Dr. T]

The truth is there will be NO difference unless you are starting frequently in temperatures BELOW -35 to -40C...as all 5W's are certified down to -30C. That is about -31 to -40F...Antarctica perhaps?

 

[Patman]

quote:

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Originally posted by Dr. T:
The truth is there will be NO difference unless you are starting frequently in temperatures BELOW -35 to -40C...as all 5W's are certified down to -30C. That is about -31 to -40F...Antarctica perhaps?

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Just because they figure out the 5w rating based on it's cold cranking abilities at -30C, don't confuse this to mean that it's going to flow equally to a 0w oil at temperatures above -30C! Because a 0w oil gets it's status from it being able to pass the cold cranking test at an even lower -35C, this would mean it will flow better under any circumstances. So when it's -10C, the 0w oil will still flow faster than the 5w oil will.

So you don't need to live in an area that gets down to -35C in order to see the benefits of a 0w oil. This doesn't mean you absolutely need it, just that it will indeed flow better. It's not like the 5w oil and 0w oil will both flow exactly the same at -30C just because that's where the 5w rating comes from.

Let me put this another way, here is one of the tests an oil must pass to get the 0w or 5w rating:

0W cold cranking vis. must be better than 6200cp@-35C
5W cold cranking vis. must be better than 6600@-30C


So think about it, if a 0w oil can have a ccv of only 6000 at -35C, imagine how low it's ccv must be at -30C!

 

[Dr. T]

The truth is you don't need it. Your car will eventually smoke and start burning oil from too thin an oil...not because you used a 5 instead of a 0.

Bottom line is heat is the problem...not cold...unless you use a 20W-50 in -35C temps OR you race and redline the thing 2 seconds after starting it. Or else we'd all be buying into the Slick50 adds and be doomed by not using it...

 

[williar]

Right on, Patman! While a 5w oil is great for cold-engine startup, 0w is even better, other things being equal.

 

[williar]

Dr T, I think both heat and cold are the problems. What we really want is an oil that excels under both extremes, and in the middle, too. An oil that provides complete protection regardless of engine temperature.

Am I wrong?

 

[Patman]

quote:

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Originally posted by Dr. T:
The truth is you don't need it. Your car will eventually smoke and start burning oil from too thin an oil...not because you used a 5 instead of a 0.

---

Don't concern yourself with the first number when it comes to oil consumption though, it's the second number that counts. If you have a 0w30 oil which is 12.2cst at 100c like GC, how can it consume more oil than a typical 5w30 which has a viscosity of only 10cst at 100c?

 

[rpn453]

quote:

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Originally posted by Dr. T:
The truth is you don't need it.

---

This is true. He doesn't need it. I do though!

I just put 0W-30 Tech 2000 Synthetic in my car on the weekend, and I'm pretty sure it turns over faster than it did with 5W-30 M1 even though it's only been as low as -18C here this week.
If it's the same price as the alternative you'd use, and performs at operating temperatures just as well, then you may as well go for the improved flow at cold temperatures.

[ November 06, 2003, 02:29 PM: Message edited by: rpn453 ]

 

[JonS]

[/qb][/QUOTE]Don't concern yourself with the first number when it comes to oil consumption though, it's the second number that counts. If you have a 0w30 oil which is 12.2cst at 100c like GC, how can it consume more oil than a typical 5w30 which has a viscosity of only 10cst at 100c? [/QB][/QUOTE]

Because at operating temps (180f) the 10.0cst oil might be thicker than the 12.0cst oil. If it has a high viscosity index number this is possible.

 

[Dr. T]

An oil's viscosity can dictate oil consumption by the following:

1. Base oil...eg. 0-30 starts with a thinner base oil vs. a 10-30

2. Amount of addatives to achieve it's spread. ie. a larger visc. spread oil may become thinner after these addatives shear or wear out

3. A thinner oil eg. 0-30 is thinner than a 10-30 at cold temperatures and therefore potentially allowing for more blow-by

 

[buster]

If a 0w-30 is a formulated using good addtives and base stock, like GC or S2k, I think they are excellent all year round oils. GC and S2k don't sheer and they are thick 30wt oils when warm which is good. An oil like M1 0w-40 is just not sheer stable enough due to what Dr.T said. The VII's are too volatile and cause the oil to sheer everytime. If M1 0w-40 was more sheer stable, i think many more people would use it. Maybe they will improve it.

 

[Patman]

quote:

---

Originally posted by Dr. T:
An oil's viscosity can dictate oil consumption by the following:

1. Base oil...eg. 0-30 starts with a thinner base oil vs. a 10-30

2. Amount of addatives to achieve it's spread. ie. a larger visc. spread oil may become thinner after these addatives shear or wear out

3. A thinner oil eg. 0-30 is thinner than a 10-30 at cold temperatures and therefore potentially allowing for more blow-by

---

But it's also possible for a 0w30 oil to be created using a thicker base stock which is simply of better quality and can naturally acheive the low cranking numbers. I suspect both Amsoil and GC 0w30 are created like this since both seem to hold their viscosity very well. I don't think either of them use much (if any) VII.

 

[Patman]

quote:

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Originally posted by buster:
If M1 0w-40 was more sheer stable, i think many more people would use it. Maybe they will improve it.

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One way they could improve it would be to formulate it so it starts out at 13cst. This way it could use less VII and would be able to stay in grade when used in turbo applications. Better to have the oil start out at 13cst and stay there than to start at 14, dip to 12 by 3k and then come back up again by 6k. This seems to be the pattern with 0w40 M1 when used in turbos.