That's not current oil, and CJ specs were not great. That was a good oil to supersede.
Doesn't get that cold in South Florida.
40°C is 104°F. Doesn’t have to get that cold to have “cold” oil pressure issues.
20w-50 is still the wrong oil.
0° weather noise is not often oil related, but based on your apparent exceptional knowledge of oils and these motors I shouldn’t have to explain that![]()