Using 0w20 Instead of 5w20 For Winter?

[TheMustangOiler]

Hiya gents,

I have a 2012 Mustang with the 3.7L that is specced for using 5w20 with Ford WSS-M2C945-A.
I live in Canada and its getting quite cold here. I know that the 5w20 is certified for down to -30C/-22F, but already at -20C/-4F I am seeing much more laboured cranking and even brief oil pressure switch going off for half a second for the oil is pumped through.
I was thinking of switching to 0w20 to slightly alleviate this. I run with Pennzoil Ultra Platinum and my new 0w20 bottle is specced WSS‑M2C972‑A1, which appears to be a pretty recent spec (2025) in addition to API/ILSAC that are also pretty new.
On Ford's "servicecontent" online manuals for more recent Lincolns with the same 3.7L motor, they advise using 0w20 in "severe cold conditions" with a spec that seems to predate or is a previous version of the 972-A1 mentioned.

The question is will this be suitable for the car? Pennzoil's data sheet also says that the 0w20 products will work in 5w20 applications (see attached image).

 

[GI_GRIFF]

Hiya gents,

I have a 2012 Mustang with the 3.7L that is specced for using 5w20 with Ford WSS-M2C945-A.
I live in Canada and its getting quite cold here. I know that the 5w20 is certified for down to -30C/-22F, but already at -20C/-4F I am seeing much more laboured cranking and even brief oil pressure switch going off for half a second for the oil is pumped through.
I was thinking of switching to 0w20 to slightly alleviate this. I run with Pennzoil Ultra Platinum and my new 0w20 bottle is specced WSS‑M2C972‑A1, which appears to be a pretty recent spec (2025) in addition to API/ILSAC that are also pretty new.
On Ford's "servicecontent" online manuals for more recent Lincolns with the same 3.7L motor, they advise using 0w20 in "severe cold conditions" with a spec that seems to predate or is a previous version of the 972-A1 mentioned.

The question is will this be suitable for the car? Pennzoil's data sheet also says that the 0w20 products will work in 5w20 applications (see attached image).

View attachment 317020

https://www.shell-livedocs.com/data/published/en-US/0dd96180-1777-4550-afe4-8fa76c219e5a.pdf

https://www.shell-livedocs.com/data/published/en-US/d28f6605-c00f-4d5b-9688-f07ad2361b96.pdf

https://www.shell-livedocs.com/data/published/en-US/9ad207d3-6b9f-4067-9838-618581c9a0f8.pdf

file:///C:/Users/J_E_G/AppData/Local/Temp/MicrosoftEdgeDownloads/6b9ff944-b940-4a93-b973-b4f3127ae0ce/IO-XX-Mobil-1-ESP-0W-30.pdf

Here are some PDS sheets on Pennzoil 0W-20 and 5W-20, and then Mobil 1 ESP 0W-30. From what I see the cold pour points are the same, except the 0W-30 Mobil ESP is slightly lower. Personally, I would run the 0W-20 Platinum or Ultra Platinum year-round if I had to run Pennzoil. However, if it was me with a car that age out of warranty, I would run Mobil 1 ESP 0w30 year-round. It has a slightly lower cold pour point than the 0W-20 Pennzoil, and you would have the benefit of the European C3 rated >3.5 HTHS oil film strength.

 

[kschachn]

Tens of long and detailed existing threads on this topic. Maybe even a hundred. So many I’ve lost count.

 

[TheMustangOiler]

Tens of long and detailed existing threads on this topic. Maybe even a hundred. So many I’ve lost count.

I checked some of the threads but none are conclusive on the topics. Closest was one person arguing the reverse.

https://www.shell-livedocs.com/data/published/en-US/0dd96180-1777-4550-afe4-8fa76c219e5a.pdf

https://www.shell-livedocs.com/data/published/en-US/d28f6605-c00f-4d5b-9688-f07ad2361b96.pdf

https://www.shell-livedocs.com/data/published/en-US/9ad207d3-6b9f-4067-9838-618581c9a0f8.pdf

file:///C:/Users/J_E_G/AppData/Local/Temp/MicrosoftEdgeDownloads/6b9ff944-b940-4a93-b973-b4f3127ae0ce/IO-XX-Mobil-1-ESP-0W-30.pdf

Here are some PDS sheets on Pennzoil 0W-20 and 5W-20, and then Mobil 1 ESP 0W-30. From what I see the cold pour points are the same, except the 0W-30 Mobil ESP is slightly lower. Personally, I would run the 0W-20 Platinum or Ultra Platinum year-round if I had to run Pennzoil. However, if it was me with a car that age out of warranty, I would run Mobil 1 ESP 0w30 year-round. It has a slightly lower cold pour point than the 0W-20 Pennzoil, and you would have the benefit of the European C3 rated >3.5 HTHS oil film strength.

All year round? Wow. There are no disadvantages to running 0W-20 then? I fear the warmer weather of the summer would be counterintuitive, no? I see multiple threads on this forum saying to run heavier weight in warmer weather/spirited driving.

 

[ammolab]

If I couldn't get HPL Supercar 0W-40 (my current universal), it's Mobil 1 Full Synthetic 0W-40.

I checked some of the threads but none are conclusive on the topics. Closest was one person arguing the reverse.

All year round? Wow. There are no disadvantages to running 0W-20 then? I fear the warmer weather of the summer would be counterintuitive, no? I see multiple threads on this forum saying to run heavier weight in warmer weather/spirited driving.

There is no disadvantage running 0W-20 all year long. 5W-20 is not a “heavier oil”. They are both 20 grade oils at temperature. The 0W rated oil may just pour at a lower temp.

You want a heavier Summer oil? Run a 0W-30 or 0W-40. Or run them year round.

 

[Wheel366]

You can use 0W-20 where it calls for 5W-20. I think it was Honda that back spec'ed from 5W-20 to 0W-20 in their engines. But if it makes you feel better, use the 0W in the cold and 5W when it is warmer.

 

[TheMustangOiler]

I'll be happy to use 0W-20 year-round as its the same price at my local Canadian Tire for Pennzoil Ultra Platinum. Is 5W20 just a relic of the past then?

 

[GI_GRIFF]

All year round? Wow. There are no disadvantages to running 0W-20 then? I fear the warmer weather of the summer would be counterintuitive, no? I see multiple threads on this forum saying to run heavier weight in warmer weather/spirited driving.

Run this Pennzoil year-round, problem solved. if you can get it. I can buy it at Walmart and on Amazon here in the states. This has the Euro ACEA C3 >3.5 HTHS and would handle your "spirited" driving just fine. The cold pour point is good on this also.

https://www.shell-livedocs.com/data/published/en-US/a65229b3-7139-454e-bf87-475cc9e0cfd1.pdf

All year round? Wow. There are no disadvantages to running 0W-20 then? I fear the warmer weather of the summer would be counterintuitive, no? I see multiple threads on this forum saying to run heavier weight in warmer weather/spirited driving.

 

[kschachn]

I checked some of the threads but none are conclusive on the topics. Closest was one person arguing the reverse.

Perhaps look a little closer. You’re new here and there’s a lot of threads you probably haven’t seen.