Two weeks ago I purchased a 2004 dakota club cab 4X4 3.7 v-6 with a five speed manual. I needed the extra room my wife had twin boys that are now one week old. The dealership was very straight forward in saying I needed to stick to 3 month or 3000 miles oil changes. They even made notes of my driving habits to determine which oci to plug into the 7-70 mile warranty. Synthetic oil would be a waste in this situation so I went with pennzoil hile mileage 5w-30. I will start using it after I hit 1000 miles and dump the factory oil. They said the factory oil was mopar. Who makes mopar oil? Anyway I thought the high mileage formula was a good choice because of the heavier viscosity at 100 c 12 and the higher number on the shear rate and also the lower noak score. At 3000 mile intervals do you think this will keep the engine clean? I think so- but that is open for debate.