Dodge knows and even the engine knows the right viscosity oil it wants, it stored an error code on my 2012 DD a long time ago when my dealer service dept used a 0w20 Amsoil for whatever reason instead of the called for 5w20, engine used oil on that oil change as well, the Pennzoil platinum is the best bang for the buck synthetic oil, Mobil 1 and Valvoline rank at the bottom for performance
Have never heard of a situation where using a lighter weight oil, regardless of brand, would set an error code. Those of us like myself, who have driven the 5.7 Hemi with MDS have definitely seen situations where using a 5W30 or 10W30 instead of the 5W20 has affected the speed of MDS activation and set a code at times. A 0W20 is the same weight as a 5W20 when hot - in effect a 20W. The lower number just means it is thinner at start-up. A 0W20 pours down to like -54, versus a -42 for a 5W20. Are you sure the dealer didn't accidentally use a 0W40, like some of the SRT engines called for? I can definitely see something like a 40W when hot causing issues with MDS on a 5.7.
As for the Pennzoil, I have tried it both on my 5.7 and a little 2.4L Jeep engine, and the Pennzoil is noticeably noisier on a cold start-up on BOTH engines. More noise = more wear, so I switched back to M1 EP 5W20. With 125K+ hard, high performance driving miles on the 5.7, no noticeable wear or noise.
Amsoil is a damn good quality oil - probably better than either the M1 or Pennzoil, but because it is a PITA to get quickly, and costly, I go with what works and what is quiet. I don't care if it cost $1 per qt., or $100 per qt., if it is quiet, engine shows little to no wear after a lot of hard driving miles, and is readily available off the shelf, then any oil is a good oil if it meets factory specs. When you state that Valvoline or M1 rank at the bottom of "performance", quantify "performance". What are you measuring or comparing? My "measurement" is the fact that M1 has held up to that many miles of performance driving, as well as commuter driving in extreme weather on the smaller 2.4, is actually QUIETER than other brands, and I know what the insides of my engine look like - exceptionally clean with little wear. If a motor oil does those things for me year in and year out, then it performs at, or above, my expectations.
