"Cool Climates" and Oil Viscosity - WTH

[Blue_Angel]

I keep seeing people referring to the local climate as an indicator of whether an engine will survive on a thinner oil or not. Like saying a 20wt makes sense up North, but it wouldn't work in the desert.

Can someone please explain to me the logic of climate affecting oil temps to a SIGNIFICANT degree?

I live in Canada (Ottawa, Ontario), what most people would condider a "cool" climate relative to much of the world. It gets over 90F here in the summer. No MFR tells people to switch oil grades seasonally anymore...

...and the same model of car comes equipped with the same oil whether purchased in Madison or Phoenix, Edmonton or Austin.

So where are these regions of "cool climate" I see people constantly referring to that would/should affect an OEM's or owner's choice of oil weight? Alaska, Yukon, Iceland? Santa's workshop?

NOTE: I'm not talking about the W rating for cold starts, I'm talking about the high temp viscosity during spirited high RPM driving.

 

[HangFire]

I guess it's about the NOACK rating? Equatorial drivers take a dim view of 20W oils.

 

[Shannow]

Blue Angel,
I agree somewhat.

During winter (mines in the low single degrees C), my Caprice has oil temperatures over 110C driving normally after 20 mins on the highway. I can't see that dropping from the GF5 5W30 economy oil is a good idea seeing as the oil temps can easily be "normal" fairly quickly.

That being said, Holden DO recommend 20W50, with 15W40 for prolonged us in snow areas.

That being said, tables like the one below are a historical fact, and DO offer different ranges .

Nissan are saying for the 510 that 10W30 is the "universal" recommnedation, but depending on what and where you are, you can choose 5W20 up to a max operating temp of 10F and can drop the W in some circumstances.

Maybe at a maximum ambient for the OCI of 10F, they don't think you'll be doing sustained high speed driving.

Similarly, the philosophy is carried through in my Nissan (but the petrol version)...the manual is universal to Oz, Europe, Asia, (Africa and south America I think)

 

[dlundblad]

From what I have seen here, a 5w something will provide enough protection for most Canadian winters. I don't know my northern geography too well, but anything waaay up north (Santa's workshop perhaps?

) should yield a 0w IMO.

A 20 weight would work fine in the desert too. More than likely, a 40 weight could be used in the 20 weight spec'd application in the same desert with no ill affects.. but a 40 weight in that same application up near Santa's workshop would be way too thick IMO. So basically, if someone lives in a warm climate and drives a 20 weight spec'd vehicle, they could use basically any 20-40 weight with no issues.. assuming the warranty won't get voided or has already expired. All that said, a northerner would be better off to stick to the recommended viscosity.

The OM for my moms Elantra recommends 5w20 for year round usage, but gives a list of weights that can be used if a 5w20 isn't available. It also gives a chart on what can be used in what temperature. Whereas my dads Jeep and truck call for 5w20 and nothing else.

At the end of the day, I think its all about fuel efficiency.

 

[Quattro Pete]

Originally Posted By: HangFire
I guess it's about the NOACK rating?

What would be the connection between Noack and cool climate?

 

[KrisZ]

Some manufacturers in NA mention in their owner's manuals that for prolonged high speed use or towing, a higher grade oil may be used instead of the 0w20 or 5w20 oil.
The problem is that they do not specify what "high speed" is, so the recommendation is only clear for towing.

For normal, passenger cars, that carry few people tops, I really don't see any reason to deviate from the "catch all" oil viscosity that manufacturers recommend.

 

[HangFire]

Originally Posted By: Quattro Pete
Originally Posted By: HangFire
I guess it's about the NOACK rating?

What would be the connection between Noack and cool climate?


Only that a high NOACK oil would be more suitable in a cool climate than a hot climate, and 20W's tend to have a higher NOACK than heavier oils (insert lament for the late PU NOACK rating here). I'm not making that case, but read the posts from the Australians and Arabian Peninsula drivers.

 

[Quattro Pete]

I'm still not following you. In general, lower Noack would be preferred, regardless of climate, IMO.

 

[Shannow]

agree...can't think of anything desirable in a high NOACK.

 

[Jetronic]

not desirable, but less detrimental is meant, I believe.

 

[HangFire]

Originally Posted By: Quattro Pete
I'm still not following you. In general, lower Noack would be preferred, regardless of climate, IMO.


Ask the Australians and Arabians. They're the ones with stories of oil boiling off to dangerous low levels and running 20w-50 in automobiles. I don't have these problems.

 

[geeman789]

I ran a car with a "real ..." oil temp gauge, one that we even tested the sensor in boiling water...

In summer, oil temps stabilized at about 100* c during normal driving, regardless of ambient temps... 10*c to 30*c, only sustained high rpm moved the oil temps up...

In the winter, however, the oil temps fluctuated around a bit... on bitterly cold days, -25*c days, oil temps never came up past about 80*c... and on average days , like -10*c days, oil temp would slowly come up to just under 100*c... but it might take 1/2 an hour...

So, on that car, which spec'd 5w30, one could say to maybe use a 20 grade in winter, and a 30 grade in summer, based on oil temp data.

You need the temperature data to make an informed decision.

 

[Blue_Angel]

Originally Posted By: geeman789
I ran a car with a "real ..." oil temp gauge...

In summer, oil temps stabilized at about 100* c during normal driving, regardless of ambient temps... 10*c to 30*c, only sustained high rpm moved the oil temps up...

In the winter... ...-25*c days, oil temps never came up past about 80*c...
...-10*c days, oil temp would slowly come up to just under 100*c... but it might take 1/2 an hour...


Thanks for your detailed post!

This pretty much proves my point, that oil temps will stabilize at pretty much the same temperatures over an extremely wide range of environmental conditions, even if it does take a while in colder conditions.

Of course this will vary from car to car based on numerous factors, but there would be a very steady trend for most cars with oil temps fluctuating by a tiny fraction of the variation in external temperatures.

Once the engine gets to the thermostat set point temperature, the oil is contained in a thermally regulated environment. On most cars the only way oil can shed heat externally is through the oil pan, so the air cooling over the oil pan is about the only thing that will change with external temperature change.

Many modern cars (like my Cruze turbo) have an oil/water heat exchanger that regulate oil temps, further reducing the impact of external temperatures.

 

[Blue_Angel]

Originally Posted By: Shannow
...tables like the one below are a historical fact, and DO offer different ranges.


Absolutely, which is sort-of my point.

Modern oils are so good at low temperatures that the OEMs are pretty much going to a single oil solution. My Cruze manual, for example, states a requirement for 5W-30 oil. However, it recommends the use of 0W-30 if the car is to be operated in extremely cold temperatures (below -20F / -29C). Both are 30wt oils, the only difference is their cranking performance at extreme temps. Page 10-11:

http://www.chevrolet.com/content/dam/Che...f/2k12cruze.pdf

I think the word "historical" is perfect. These days with these oils, I think we just pick a viscosity grade that works when hot, then make sure the W rating covers our coldest starts and quit worrying about it.

 

[Shannow]

Originally Posted By: Blue_Angel
I think we just pick a viscosity grade that works when hot, then make sure the W rating covers our coldest starts and quit worrying about it.

That, my friend, is perfect logic in my mind !!!

 

[Blue_Angel]

Originally Posted By: Shannow

I missed this earlier. The * on the 5W-20 oil option says "Not recommended for sustained high speed driving", which suggests they don't think a 20wt oil is thick enough for normal operation even at extremely low outside temperatures.

By "normal" I mean not changing your driving habits based on oil choice.

 

[Garak]

Originally Posted By: Shannow
Originally Posted By: Blue_Angel
I think we just pick a viscosity grade that works when hot, then make sure the W rating covers our coldest starts and quit worrying about it.

That, my friend, is perfect logic in my mind !!!

Absolutely. That's the way I've preferred to do it for many years. It's nice to be able to avoid seasonal oil changes.