When did Ford change the recommended engine oil for the GT?

JFALK68

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Last week, my wife took delivery of her 2021 Mustang GT Convertible (PP1, 401A, 10SP, MagneRide, Twister Orange). I had spent the better part of 2018 obsessing about Mustang GTs (before taking a break after buying a different car), so I felt pretty confident I knew everything I needed to know about this car.

So imagine my surprise when I saw that Ford now officially specs 5W-30 oil for the GT in the owners manual. To make sure I wasn't looking at the wrong information, I looked up the recommended engine oil on the Amsoil website and it indeed comes back as 5W-30. However, if I switch to a 2018 Mustang GT, the recommended oil is still 5W-20. (Of course, my assumption is that the engine itself has not changed in any meaningful way.)

I recall from a few years ago heated debates about using 5W-20 vs 5W-30. In short, one camp took the position that Ford engineers know best and why would you put your warranty coverage at risk by going with another type of oil. The other camp believed that Ford only recommended 5W-20 to meet CAFE requirements and 5W-30 will provide better protection (especially if you ever put any amount of stress on the engine).

This raises a few questions for me:
When did Ford make this change? Why doesn't Ford change the recommended engine oil for GTs from previous years (and would they seriously deny a warranty claim for using 5W-30 at this point)? Does this end the 5W-20 vs 5W-30 debate (or do we get to argue about 5W-30 vs 5W-50 now)?
My 2022 Mach 1’s oil cap states 5W30.
Last week, my wife took delivery of her 2021 Mustang GT Convertible (PP1, 401A, 10SP, MagneRide, Twister Orange). I had spent the better part of 2018 obsessing about Mustang GTs (before taking a break after buying a different car), so I felt pretty confident I knew everything I needed to know about this car.

So imagine my surprise when I saw that Ford now officially specs 5W-30 oil for the GT in the owners manual. To make sure I wasn't looking at the wrong information, I looked up the recommended engine oil on the Amsoil website and it indeed comes back as 5W-30. However, if I switch to a 2018 Mustang GT, the recommended oil is still 5W-20. (Of course, my assumption is that the engine itself has not changed in any meaningful way.)

I recall from a few years ago heated debates about using 5W-20 vs 5W-30. In short, one camp took the position that Ford engineers know best and why would you put your warranty coverage at risk by going with another type of oil. The other camp believed that Ford only recommended 5W-20 to meet CAFE requirements and 5W-30 will provide better protection (especially if you ever put any amount of stress on the engine).

This raises a few questions for me:
When did Ford make this change? Why doesn't Ford change the recommended engine oil for GTs from previous years (and would they seriously deny a warranty claim for using 5W-30 at this point)? Does this end the 5W-20 vs 5W-30 debate (or do we get to argue about 5W-30 vs 5W-50 now)?
My 2022 Mach 1 states 5W-30 on the cap.
1660669548028.jpeg

 

Vlad Soare

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When operated at high temperatures above intended use, yes. A 5w20 oil at 260* (130*C) is no longer the same viscosity as at 212* (100*C) where it was intended to be operated at. Thus the need for a thicker oil to begin with so that as it gets heated up and thins out it maintains the minimum viscosity needed.
Of course, higher temperatures require higher viscosity grades, that's a given.
But if you drive on the street, and the CHT never exceeds 95°C/203°F, and Ford recommends 5W20, then can we take for granted that 5W30 would give better engine protection? Twenty years ago we could have, but today I'm not so sure.
 
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EFI

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But if you drive on the street, and the CHT never exceeds 95°C/203°F, and Ford recommends 5W20, then can we take for granted that 5W30 would give better engine protection? Twenty years ago we could have, but today I'm not so sure.
Oh 100% no, for street driving there is literally 0 need for any thicker oil than recommended.
 

Chomperr

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Of course, higher temperatures require higher viscosity grades, that's a given.
But if you drive on the street, and the CHT never exceeds 95°C/203°F, and Ford recommends 5W20, then can we take for granted that 5W30 would give better engine protection? Twenty years ago we could have, but today I'm not so sure.
What about for those of us in desert climates? I’m thinking of switching to 5W-30 on my 2018. I drive it regular street traffic, no tracking. It gets extremely hot here in southern Nevada. I think I’d switch back to 5W-20 in the winter. Any issues with this?
 

K4fxd

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I think I’d switch back to 5W-20 in the winter.
Why?

What about for those of us in desert climates?
If ambient is over 100F even 10w-60 will be fine. My only concern with a 10 weight is the cam journals but the 60 will cling better so it should be fine even at 30 degree temps.

Ford specs 5w-50 for the same engine. 5w-30 will not harm anything. Remember 5 is the cold thickness so the same for all. Hot protection is better with a larger secondary number. Desert I'd use 5w-50
 


Firsttexan

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Last week, my wife took delivery of her 2021 Mustang GT Convertible (PP1, 401A, 10SP, MagneRide, Twister Orange). I had spent the better part of 2018 obsessing about Mustang GTs (before taking a break after buying a different car), so I felt pretty confident I knew everything I needed to know about this car.

So imagine my surprise when I saw that Ford now officially specs 5W-30 oil for the GT in the owners manual. To make sure I wasn't looking at the wrong information, I looked up the recommended engine oil on the Amsoil website and it indeed comes back as 5W-30. However, if I switch to a 2018 Mustang GT, the recommended oil is still 5W-20. (Of course, my assumption is that the engine itself has not changed in any meaningful way.)

I recall from a few years ago heated debates about using 5W-20 vs 5W-30. In short, one camp took the position that Ford engineers know best and why would you put your warranty coverage at risk by going with another type of oil. The other camp believed that Ford only recommended 5W-20 to meet CAFE requirements and 5W-30 will provide better protection (especially if you ever put any amount of stress on the engine).

This raises a few questions for me:
When did Ford make this change? Why doesn't Ford change the recommended engine oil for GTs from previous years (and would they seriously deny a warranty claim for using 5W-30 at this point)? Does this end the 5W-20 vs 5W-30 debate (or do we get to argue about 5W-30 vs 5W-50 now)?
I have been running 5W-30 on my 2019 since I bought it.
 

 
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