Noticed I’m burning about a quart every 4-5k on my 3.6 Pentastar. The engine has 128k with a 60/40 mix of hwy and local driving. It’s been run on 5W20 since 45k. Should I try a thicker oil to see if it slows down consumption or perhaps go with a high mileage 5W20? My understanding is that these engines are not burners so I’m a little concerned. The stealership suggested it may be a head gasket issue which I’m not sure I agree with. Any particular brands of oil or weights that these engines perform well on?