Automotive

5W20 syn oil for vehicle with spec for 0W20?

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  • May 26th, 2015 7:31 pm
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[OP]
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Sep 23, 2013
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5W20 syn oil for vehicle with spec for 0W20?

I have stocked up syn oil since day 1. But my vehicle died after close to 400 k km. The new vehicle requires 0W20. Can I use 5W20 assuming warranty is not an issue (I am not to tell anyway)?
Daniel

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Deal Expert
Mar 25, 2005
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It should be fine as long as the API spec is current. Beware that manufactures have completed UOA in warranty cases.
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Feb 24, 2007
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danieltoronto wrote:
May 26th, 2015 6:41 am
I have stocked up syn oil since day 1. But my vehicle died after close to 400 k km. The new vehicle requires 0W20. Can I use 5W20 assuming warranty is not an issue (I am not to tell anyway)?
Any chance you could return the oil and swap it with 0 weight from the original supplier/vendor?

I am with Kasakato on this also. While the difference between 0 weight and 5 weight is negligible, any warranty work may come back and bite you in the ass.
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Mar 30, 2010
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I wouldn't care, but for extra peace of mind, get some 0w-20 to use in the winter and run the 5w-20 in the spring/summer/fall.
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Oct 26, 2008
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The reason Japanese automakers started using 0W20 oil was solely to achieve a 0.5% - 1.0% improvement in U.S. EPA fuel economy numbers.

And that improvement only applies for a cold start until the engine has warmed up.

So it's not that their engines were designed in the first place with tighter tolerances that they absolutely need such a thin oil.

I would think that using a 5W20 year-round will not cause you any issues. Any slight loss in fuel economy will be more than offset by the savings in the relative price of 5W20 vs. 0W20 oil.
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Mar 17, 2003
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If you are covered by warranty you need proof that you were using the same viscosity required to validate warranty. UOA have been done in warranty claims but honestly I dont think you have to worry about it. I am performing oil changes on my 15 WRX myself but I am sticking with the viscosity recommended for warranty and retaining all receipts , using factory filter and documenting mileage of changes, which are well below manufacture OCI
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Jan 7, 2014
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macnut wrote:
May 26th, 2015 9:52 am
The reason Japanese automakers started using 0W20 oil was solely to achieve a 0.5% - 1.0% improvement in U.S. EPA fuel economy numbers.

And that improvement only applies for a cold start until the engine has warmed up.

So it's not that their engines were designed in the first place with tighter tolerances that they absolutely need such a thin oil.

I would think that using a 5W20 year-round will not cause you any issues. Any slight loss in fuel economy will be more than offset by the savings in the relative price of 5W20 vs. 0W20 oil.
I thought that playing around with viscosity is not recommended. Can you provide some more references to support your statement.
I mean I can buy the idea that in summer 5w20 can replace 0w20 as the cars come to operating temperatures pretty quickly but in winters too ? Not sure...
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Oct 26, 2008
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It is generally agreed that the overall difference between 0W20 and 5W20 oils is small relative to comparing other grades (such as 0W30 vs. 5W30).

I believe that Toyota, for example, had or used to have on some of its oil filler caps "use 0W20 or 5W20".

A better question than should I use 0W20 or 5W20 is whether using such a thin oil is in your best interests as a long-term car owner with varying demands put on your engine throughout the year.

That is, are car manufacturers putting too much emphasis on their fuel economy ratings at the expense of your real-world engine performance and long-term wear rates?

See, for example: http://www.machinerylubrication.com/Read/518/motor-oils

In moderate climates, including the GTA, I don't think ambient temperature has as much effect on a car's warmup time as generally imagined.

Sure, you feel the effect of the heater not putting out when you need it, but that is misleading. Other factors such as car kept outside or in a garage are more important to warmup time.

For the present discussion, this is why I feel that fretting over 0W20 vs. 5W20 is overdone - unless maybe you live where winter temps. regularly reach -40.
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Asker123 wrote:
May 26th, 2015 10:03 am
I thought that playing around with viscosity is not recommended. Can you provide some more references to support your statement.
I mean I can buy the idea that in summer 5w20 can replace 0w20 as the cars come to operating temperatures pretty quickly but in winters too ? Not sure...
http://www.bobistheoilguy.com/forums/ub ... ost2576182

From Mobil website, comparing Mobil 1 0W20 and 5W20:

SAE Grade - 0W-20 - 5W20
Viscosity @ 100ºC - 8.7 - 8.9
Viscosity @ 40ºC - 44.8 - 49.8
Viscosity Index - 173 - 160
HTHS Viscosity - 2.7 - 2.75
Flash Point - 224 - 230

M1 AFE 0W20 is very slightly thinner than 5W20 at operating temperature, but much thinner at start up therefore lubricate engine better every time you start your cold engine. Similar for other brands.
No reason to use M1 5W20 if you can find AFE 0W20 easily.
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Feb 8, 2014
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I would not do it, cold starts cause the most wear and having thicker oil on an engine speced for thinner oil will likely reduce its life a bit
How much extra oil are we talking here?
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Jan 27, 2006
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I've been using German Castrol 0W-30 on my current and last two cars. *knock-on-wood* No issues whatsoever.

IIRC, they call for 5W-20 or 30.
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Oct 26, 2008
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No question that cold starts at any time of year are a main contributor to engine wear over time.

However, there are other things to consider regarding how well your engine oil is going to protect your engine in certain circumstances.

What happens when driving on the highway if your engine overheats a bit because the thermostat or water pump or something is on the fritz?

Which oil is going to provide better protection then? The 0W20? Or the 5W20? Or maybe that's when you would be better off with a 0W30?

The auto maker has to juggle their priorities in specifying an oil grade, but those priorities don't necessarily align with what a typical car owner is going to encounter in real life.

As the article I linked to earlier asks - does anyone have an explanation why Ford specified a thin oil for its engines in N. America but not for the very same engines in Europe?

That article may be a bit out of date now, but don't underestimate the role of CAFE and oil industry marketing in this debate.
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macnut wrote:
May 26th, 2015 2:57 pm
No question that cold starts at any time of year are a main contributor to engine wear over time.

However, there are other things to consider regarding how well your engine oil is going to protect your engine in certain circumstances.

What happens when driving on the highway if your engine overheats a bit because the thermostat or water pump or something is on the fritz?

Which oil is going to provide better protection then? The 0W20? Or the 5W20? Or maybe that's when you would be better off with a 0W30?

The auto maker has to juggle their priorities in specifying an oil grade, but those priorities don't necessarily align with what a typical car owner is going to encounter in real life.

As the article I linked to earlier asks - does anyone have an explanation why Ford specified a thin oil for its engines in N. America but not for the very same engines in Europe?

That article may be a bit out of date now, but don't underestimate the role of CAFE and oil industry marketing in this debate.
I'm not a gasoline engine design engineer, but your essentially arguing that all of us should go with oils the manufacturer says we should not use. They may use tighter tolerances because they have speced thinner oil, how will the thicker oil affect that? We simply do not have enough technical information to second guess the manufacturer.
I use synthetic because it flows better and protects better at hot and cold extremes, but i'm not ready to be a ginuea pig in "i am smarter then the design engineers". Its possible you might be, but its equally if not more possible you could cause problems even though i agree thinner oil is meant for better mileage.
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[OP]
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Sep 23, 2013
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NORTH YORK
Wow guys. I hardly ever go over to this forum as this is a new subject for me. Got a lot to learn. All the above makes sense. I will probably be able to pass the 5W20 oil to my daughter. It is PITA to find sale of 0W20 though (if any at all).
Daniel

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