There's synthetic 5w20 on sale nearby but I want to ask something here first. I don't put a lot of miles on my car so I usually do one oil change per year. The car is parked outside and is a Kia Forte. In my city we generally will see 5-10 days a year where it will get down to -20 F but most of the time in the coldest months it is probably between -10 f and 25f. Very rarely we will see lower than -25. Summers are mild with only a handful of days over 85 generally. From what I read, 5w is safe to about -22 F. Would you run this year round in these temps or do you think 0w would be a necessity here?
At which temp range would you switch from 5w to 0w?
- Thread starter Whammo
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The 5w20 pour point should be below -45F.
Even though overnight lows might hit that, it's typically for an hour at sunrise, and cold soak/ inertia can lessen the impact. In a "city" you also get "heat island" effects from all the buildings around you. And while we all have places we need to be, what, realistically, are the odds you'll be cranking that thing on the coldest point in the year?
Assuming you do buy and use it, new oil has pour point depressants so time your annual OCI for December.
Does this Kia have one of the troublesome engines?
Even though overnight lows might hit that, it's typically for an hour at sunrise, and cold soak/ inertia can lessen the impact. In a "city" you also get "heat island" effects from all the buildings around you. And while we all have places we need to be, what, realistically, are the odds you'll be cranking that thing on the coldest point in the year?
Assuming you do buy and use it, new oil has pour point depressants so time your annual OCI for December.
Does this Kia have one of the troublesome engines?
It's has one of the newer (better?) Atkinson 2.0 engines.
edyvw
$50 site donor 2026
No it should not. That depends on base stocks, and most 5W20 have higher pour point in 30's.
Which is irrelevant for when it comes to CCS or MRV. That is why pour point is not used anymore to evaluate cold performance.
It wasn't until this last couple years that I have made the switch to 0w oils. Why? We have quite a few vehicles, can only plug about two of them in at the house, at a time. Just making things easier for unaided cold starts. What's cold? We see regular -30c and into the 40s.
Otherwise, my fleet has seen nothing more than 5w20/30 for the gassers and 10w30 for the 6.7 diesel, (did 5w30 once) for years.
5w will serve you absolutely fine at -40. The real issue is ensuring your battery is kept topped off.
Don't overthink this.
Otherwise, my fleet has seen nothing more than 5w20/30 for the gassers and 10w30 for the 6.7 diesel, (did 5w30 once) for years.
5w will serve you absolutely fine at -40. The real issue is ensuring your battery is kept topped off.
Don't overthink this.
No switch needed, I use a 0W in everything I drive 
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Is that actual temperature or wind chill ?
-22º F is the minimum 5W has to be "good" at, but synthetic can, and likely does, go lower. You can safely run 5W. Is it parked inside or outside ?
It is parked outside. That -22-25F is roughly the coldest it will get all year without the windchill.
Patman
Staff member
I like to give myself a big margin of safety so I run 0w even if we rarely get below 0F here. Since the winter rating can change as the miles add up I would not want to start with a 5w and have it become a 10w
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I’m interested in the thoughts on this, because i park both my vehicles outside too. I’ve had the standard practice of using 5W30 spring summer and autumn, and i switch back to the OEM recommended 0W20 for the cold months just because im not knowledgeable about how well 5W30 flows in my climate (Canadian Border in the NE USA) where temps get down to -25f a few times per winter, like this past winter, for over two weeks steady.
I didn’t use a 0W in anything u til the last couple of years and still use a 5W in 2 vehicles. You’ll be fine. I’ve started vehicles in -38 and had oil pressure and no knocking or lifter noise. They turn over slow. When it’s that cold I let my vehicles idle for 15 minutes and then take off slow because of gear lube, it takes a bit to get it coating the ring and pinion. There were some mornings the ATF didn’t make it to 100F after getting to work 20 minutes later.
Anymore when the forecast is -10 or colder I’m looking for an extension cord. Usually it’s clear outside and and it drops colder than -10.
Anymore when the forecast is -10 or colder I’m looking for an extension cord. Usually it’s clear outside and and it drops colder than -10.
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With the CVT in the Subaru, it sucks cause even after idling for ten to fifteen minutes, the CVTF is still no where near operating temp, so same story, after a 20 minute ride to work its rarely fully warmed up during those cold spells. Someday I’ll have a garage, lol.
Did you mean Siberia?
Yeah there also. Thanks
There is no reason to switch back and forth. If you live in an area that has cold winters, like you, use a 0W-XX all year round. If you live in a warm climate, where winter means perhaps one or two snow days a year, if that, then use a 5W-XX all year round. The more we learn, the more we know, your engine will be well protected.
Regular oil and filter changes with a quality motor oil is immensely more important than worrying about 0W vs 5W.
Regular oil and filter changes with a quality motor oil is immensely more important than worrying about 0W vs 5W.
0w-20. Easier start up in cold.
My 2010 Kia Forte, 2021 Hyundai Tucson, 2008 Honda CRV all call for 5W-20, year round some with option of 5W-30 year round depending on temperature. I have used 0W-20 if that was what I got on sale.
If you get a good price I'd run the 0W-20, 5W-20, 5W-30 with no issues.
If you get a good price I'd run the 0W-20, 5W-20, 5W-30 with no issues.
Both grades are suitable for these temperatures. 0w oils will crank easier though. Not an issue with modern engines for the most part.
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