Thanks, that helps. I missed the 100 F limit for 5W-30. Guess the end of the arrow is really the end, duh me. I'm also in PA and although it rarely gets to 100, we did have high 90's in the past for a few days in summer. Now with global warming, it seems PA is gettting cooler in the summer while the other states are heating up. Warmer winters and cooler summers.
Since I'm using a semi-synthetic, I suspect it's going to be a little more robust near 100 F, Conoco-Phillips/Kendall. So far it's not the same as dinosaur 5W-30. Mind you, I'm not saying it's the same as 100% synthetic, not that I would know but it definitely is smoother and does not seem to burn up oil as easily. I am not using as much oil as with
10W-30 or 5W-30 dinosaur. The 10W-30 is good down to 0 F and the 5W-30 is good up to 100 Fahrenheit or 38 C. Easy for me to remember that now. In the past I had used 10W-30 in winter and 10W-40 or such in summer in older cars.
You're also right about the choices. The manuals clearly state if a choice, use 5W-30, for the starting "to reduce low temperature cranking effort" (but not for the 2.5 Liter engine above 0 C. or 32 F.)
Now when I get it together, I should get another analysis from Blackwell Labs just out of curiosity. Funny how the mechanics get a bit bent of shape with all the chemistry that comes back. Guess they feel threatened since they probably never had chemistry. Or as one said, he did not need lab reports. He has his ears! But I don't have his ears, as I explained to him so I need the chemistry.
But it's fun to read those lab reports and they are around $20. The last one said my oil fine given my engine and its mileage but that it was more like a 5W-30. I suspect the mechanics knew my car preferred
5W-30 in winter and gave me that although I had asked for 10W-30 near the winter. I do wish they had explained this to me though.