Originally Posted by demarpaint
Originally Posted by IndyFan
Again, just to be clear, the 2017 and up Grand Cherokee and the 2018+ JL (Not 2018 JK, but JL) Wrangler, and the Gladiator, 100% for certain, have the Pentastar Upgrade that specifies 5 quarts of 0w20. It never had, even overseas, a weight specification greater than 20. The previous generations of t The fact my JL Rubicon, even with 35" tires, can get 21.5 mpg is significant evidence this engine is different. When traveling with two 2 door JK's with Pentastars, which were lighter and had the same size tires and final drive gearing, we saw nearly a 4mpg difference in gas mileage over 2000+ miles of driving the same trip together. Folks, that's not the 20 weight oil, that's a redesigned engine. (Ok, the aero is supposed to be better with the JL, but it isn't 4mpg better.)
I hope that helps clear up some of the confusion between these two generations of the Pentastar.
FTR I'm sure you already know this. I'm not sure if you're talking 6 speed stick, which the JK and JL have. The JL 6 speed is not the same as the JK 6 speed, it is supposed to be an improvement. With regard to the automatic, the JK uses the NAG1 5 speed, the JL the ZF 8 speed. I'm pretty sure that would account for most of that 4 mpg difference.
Yep, I have both, a JK Rubicon 6 speed and a JL Rubicon 6 speed. The JL's Aisin transmission is indeed vastly superior to the JK's NSG370. However, I think several factors are at play for that mpg increase, including aero, probably the transmission, and the engine. I've driven enough Pentastars to know that the PUG is stronger and revs just a little more freely, IMO. Not by alot, but it's there. Read up on the PUG. They did a great deal of friction reducing in the engine. There is significantly reworked with both power and fuel economy in mind.
I've heard people talking as if 5w20 is a thicker oil than 0w20. Take a look at kinematic viscosity and you'll see that Mobil 1 EP and AP are thicker at 100 degrees C than many 5w20 oils. I believe they are 8.7 and 8.8, respectively. They also have higher flash points and lower pour points. I believe them to be superior oils to the 5w20's, and have more PAO content.
Back to the conversation...another 0w20 that I think is good is Pennzoil Gold. It is advertized as a blend but the specs look really good. I'm betting it was the factory fill on my Jeep.