I have 4 1st gen intrepids, 2-3.3L and 2 3.5L. I disagree with the earlier poster who says the 3.5 is junk. Its a good motor that makes good power.

In my opinion you should always take care of the known issues first and the waterpump and timing belt are overdue. Change those and my guess is your overheating problem will go away. I've done both mine 3.5s now. I think the second one took me a couple hours to do. You can borrow the balancer tool from an autozone. Remove the brace accross the radiator and the fans and then you can remove the belt covers and radiator hoses. Pull the old pump and take it with you to the parts store, there are to pump versions availiable 3 and 6 bolt. Total is under $100.00

Ken