5W30 vs. 0W30

[bdai]

I expected this to be a common question, but I haven't had much luck searching.

My car specs 5W20 oil, but Petro Canada (which I run because of cost) only has xW30 synthetics. The engine is spec'd for 5W30 in Europe, so there won't be a problem running that. However, I'd still like to run a lighter oil if possible, so I'm wondering if the viscosity modifiers in the 0W have much bearing on how the oil behaves at operating temperatures. Here's the info I got off the PC site, but I don't know how to translate cSt and SUS units into physical behaviour.

0W30 (5W30):
cSt @ 40'C : 57.6 (58.2)
cSt @ 100'C: 10.4 (10.3)
SUS @ 100'F: 292 (295)
SUS @ 212'F: 61.1 (60.7)

Thanks for your help.

 

[ewetho]

Synthetic 0W instead of 5W has been covered numerous times but once again NOT an issue.

Just better cold flow starting viscosity in most occurrences and thus better milage and possibly better wear numbers from start up wear.

 

[bdai]

I understand the differences in viscosity during starts, but I'm more concerned about operating viscosity. From the numbers I posted, it appears that the 0W30 is actually slightly thicker at operating temps, but I'm not sure if I fully understand the units.

 

[rpn453]

Yes, the 0W-30 is a little thicker, by a laboratory-measurable amount, than the 5W-30 at 100C, and a little thinner at 40C. Not by enough that you'd notice though. Your engine certainly wouldn't mind either oil.

 

[bdai]

Thanks. I've been keeping a bottle of 5W30 in my car to see how it flows in the cold, and it was still very fluid when we saw -22C a few days ago. I'll stick with that oil then.

 

[hominid7]

Keep in mind the 100*C temp viscosity may not be where your car spends most of its operating time. The 0w30 not only is thinner at 100*C but throughout the lower temps as well, so i would likely go with that.

 

[bdai]

The 0W30 is actually thicker at 100'C. I think my stock thermostat is 180'F.

 

[Auto-Union]

Maybe the 0w is formulated thicker +100c because it is more likely to shear back?

 

[bdai]

Does that work in my favour? Should I go with the 0W and hope for it to shear to a lighter weight than the 5W30?

 

[Patman]

Where are you getting Petro Canada oil so cheap? I've only seen Petro Canada oil at the gas stations and it's very costly.

Petro Canada does make a 5w20 conventional oil by the way. Do you really have your heart set on running synthetic? If so, why not go for Canadian Tire's 5w20 synthetic? It's often on sale for $20 for a 4.4L jug.

 

[JohnnyO]

I ran 0w-30 M1 one winter and the wear metals were higher than with 5w-30. .02.

 

[bdai]

You can buy cases of 12x1-L PC Synth at bulk dealers that are listed on PC's site. Specifically, I pick up a case from Bowman Fuels in Barrie every time I head up to Orillia. The cost works out to be almost exactly the same as Formula 1 synthetic, except I've heard that Formula 1 doesn't have as robust an additive pack.

 

[bdai]

Oh, the price I'm basing it on is the non-sale price, by the way. The Petro Canada works out to about $27.50 / 4.4 L pre-tax, which I think is slightly cheaper than F1 synth ($29 / 4.4 L, isn't it?).

 

[bdai]

Quote:

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I ran 0w-30 M1 one winter and the wear metals were higher than with 5w-30. .02.

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That's interesting. What engine was this in? Did it originally call for 5W30?

I'm assuming from this that the 0W30 probaby protected better at startup, but didn't do as well at operating temps. Perhaps it's a trade-off.

 

[Patman]

Quote:

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Oh, the price I'm basing it on is the non-sale price, by the way. The Petro Canada works out to about $27.50 / 4.4 L pre-tax, which I think is slightly cheaper than F1 synth ($29 / 4.4 L, isn't it?).

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I think that is about that price, but there is no point in comparing the regular price of the Petro Can stuff (which probably never goes on sale) The CT stuff goes on sale quite often. So if it's price that you're basing your decision on, the CT stuff is going to be the cheaper way to go, by far.

 

[bdai]

Price is one of the bigger factors, but I'm also basing it on the fact that I've only heard good things about Petro Canada, but store-brand oils always have that "mystery-oil" feeling to them. Other than periodically checking the MSDS sheets, it's hard to tell if Canadian Tire ever switches oil suppliers. A recent thread on here added even more confusion where Terry said something I took to mean "Shell is a licensed brand in Canada, and someone else supplies their base oil."

 

[Patman]

That is a good point, and I've also heard nothing but good things about Petro Canada oil too.

I'd love to give their oil a try in my wife's car someday.