Well the noise I found out is the motor and I guess is normal for the 4.2. i heard a F150 when reving the motor sounded the same. I think the 5w20 makes this sound more .. I am getting ready to switch to mobil 5w30 full synthetic. I was just waiting for the miles to get a little higher. I think this will help with that noise.. It has in other cars and vans I use it in.. Tends to make the engine run smoother,to me any way.. Ill post back with results later.