Do Northstars have the sludge problems that all chrysler 2.7s have?
Sort of...the Northstars have oil rings on the pistons that "sludge" and need to be cleaned if that occurs. Synthetic oil prevents this. I went almost 90K on my 1995 Eldorado using Mobil 1 every 3K miles with out having to add 1 drop in between changes. Also, the 40 weight handles the heat better IMO.