Proper Oil Do you have an automatic? If so, your engine has a Multiple Displacement System (MDS). Under very specific situations like low speeds, low throttle, low loads (but not idling), the Powertrain Control Module shuts off four of the eight cylinders. The MDS may also deactivate cylinders during some steady-speed, low acceleration and level grade driving conditions. It does this with a complex combination of four solenoids, an oil temperature sensor and eight unique valve lifters. The PCM monitors the health of the MDS. This monitoring means the weight of oil used in the 5.7 auto. is more critical than in the non-MDS engines. Vehicles with the Multiple Displacement System must use SAE 5W-20 oil. Failure to do will result in improper operation of the MDS. I have a 6.1 engine and use Mobil 1 synthetic. You can also use a synthetic if you use the proper weight.
The Owner's Manual for my '11 R/T (5.7 with Auto) doesn't call for synthetic .... but I still use it. The previous owner kept the oil changed on a regular basis but used regular "dinosaur" oil. The first weekend that I had the car, I switched to put Pennzoil Ultra 5W-20 in it with a Bosch filter. I only chose Pennzoil over Mobil 1 (my normal go-to) because Pennzoil was on sale and Mobil 1 wasn't. My wife's '13 Charger R/T has had only Mobil 1 5W-20 since its first oil change at 1,000 miles. Both cars have been trouble-free.
