From what I have gather thicker weight oil will add extra engine protection in high stress situations (High HP, Boost, High RPMs, High Static Compression Ratios, High Heat, etc.) that is why the heavier weights are recommended to 'maintain' the layer of oil between the moving metal parts i.e. rod bushings/bearings, main bearings, etc..

However I have seen in the past some national magazine 'engine' dyno testing where the viscosity of the oil was the 'only' change made using the same brand of oil to a thinner weight & keeping all the operating perimeters equal on the engine dyno. The resulting improvement was 30+ HP on a yester-year n/a not so high of a HP engine.

Then take into consideration that a thinner oil (requires less HP to turn the engine oil pump/s) will reach all the parts of an engine quicker reducing cold start up engine wear. However I have seen lately the exception where a 0w20 oil "Kicked A$$" in an oil test as far as engine wear goes on all the other "well respected" brands of oils regardless of the viscosity used.

BOTTOM LINE: "I" would use the thinness oil that still 'protects' from engine wear. The newer cars generally have tighter bearing clearances so they can maintain the oil pressure/layer with the improved thinner oils of today. Oh, and don't forget its easier (less drag) for piston rings to scrap thinner engine oil off cylinder walls. PS: it's also easier/less stressful to pump water than maple syrup.

 

Mobil 1 15W50, all year since day one, wear numbers are lower than baseline according to Blackstone.

 

15 cold weight oil is pretty darn thick when it's 8 degrees out

 

agreed but, not an issue in the south.........

 

Amsoil offers 5W-50

 

Changed mine in the garage a few months ago - easy peasy. Went with the OEM Mobil1 0w40 ESP and AC Delco PF64 filter. Ordered it from Speedway Motors here -

https://www.speedwaymotors.com/Mobil...it,386340.html

 

^$104 buck for 12 quarts and a filter?

I just picked up one of those 12 quart boxes with the pour spout at Walmart for $54
No filter but still, a filter sure isn't worth the additional $45

 

Bet its not the 0W40 ESP formula - if it is, buy them all because that's a steal!

 

I got the Euro stuff
What does ESP stand for?

 

You did not get the ESP for that price. You got the euro which is cheap and plentiful.

I also bought the “Franzia style” Mobil 1 0W-20 for my Silverado, but the ESP is not sold that way. Hopefully it will soon.

 

same here. I bought that “kit” from Speedway as well a few weeks ago.

 

so what actual difference is there?