Are 0w20 and 5w20 100% interchangeable?

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Any exceptions? Assuming both are SN plus is there any reason you shouldn't run one or the other? It's understood that 0wXX is the better option for colder climates.
 
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Originally Posted by atikovi
The owner's manual would be the place to look for the best choice. I assume 0w would give slightly better gas mileage.

That's not true. A 0w20 can technically be thicker than a 5w20.
 
Originally Posted by atikovi
How so?

At operating temperature both are 20 grade oils and there's a range for 20 grade oils. Some are a tad thicker and some thinner. The number before the W has nothing to do with viscosity when the oil is hot. The 20 weight viscosity range is between 6.9 - 9.3 cSt. So technically a 5w20 can be 6.9 cSt @ 100c where a 0w20 can be 9.3 cSt @ 100c.
 
Originally Posted by Davejam
They have different HTHS specifications which is important. So, No, not technically speaking.


Not necessarily. Both 0W-20 and 5W-20 have a minimum required HTHS of 2.3 mPa.s. as per SN Plus.

Many SN Plus oils meet the ACEA C5 spec (at least in europe) in which case the minimum HTHS is 2.6 mPa.s
 
Originally Posted by Char Baby
All 0W20s are synthetic but not all 5W20s are.


This. This is why the manual mandate 0w20 for 10k OCI so people won't put in 5w20 dino and blame it on the manufacturer.
 
Originally Posted by Char Baby
All 0W20s are synthetic but not all 5W20s are.

I think Pennzoil and Motorcraft have a 0w20 syn blend.
 
Originally Posted by jayjr1105
Originally Posted by Char Baby
All 0W20s are synthetic but not all 5W20s are.

I think Pennzoil and Motorcraft have a 0w20 syn blend.

Shouldn't respond before checking things out but....

Lots of syn-blend oils (5w-20 and 5w30 still market themselves as conventional because they have "syn-blend" brands marketing themselves at a higher price point.

Could these "syn blends" be all synthetic (i.e. group 3) and marketing themselves as syn blends because there's a "synthetic" at a higher price point?

It will be interesting to see how this all shakes out when SP oils hit. Lots of branding confusion ahead.
 
Generally if you're in a warmer climate, or rather you don't live in like Northern Canada or Northern Scandinavia where 5w20 may become unpumpable during the extremes of the winter , I'd stick with 5w20 should have a thicker base oil with less VII content which should make it more shear resistant.
 
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Originally Posted by Davejam
They have different HTHS specifications which is important. So, No, not technically speaking.


Some are the same and some the difference is so small it's nothing to worry about.
 
And I mean less VII when comparing a full synthetic 5w20 to a 0w20 in the same product line generally. Dino 5w20 could have a lot of VII in it.
 
Originally Posted by ka9mnx
No, API minimum HTHS for all 20's is 2.6.


Did that not change in 2018 in the latest edition of SN and SN plus after a motion to ballot? As per SAE J300 you are correct, but I thought that API had opened up the tolerances a little with the focus on resource conservation.

[Linked Image]
 
Originally Posted by Char Baby
All 0W20s are synthetic but not all 5W20s are.


Wow... there have been several 0w20 synthetic blend oils on the market for a few years now.
 
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