I am a serious Cadillac Northstar enthusiast. I am just writing to encourage those to work on their own Northstar engines as opposed to taking it to the dealer. A little bit about my 1999 Deville Concours, black on black, tinted windows, tinted rain gutters, self made three inch stainless steel tips. The dealer wants $450.00 for a tune up, I did it myself, plugs and wires in 55 minutes. I installed a new water pump after buying the special tool from Autozone for $35.00, I probably saved $500.00 minus the part and tool, total time, one hour and fifteen minutes. New brakes, the good ones, Bosh Ceramics, new Air Hog air Filter element, $52.00, five minutes. I also have the Giavanna G-racing rims and Toyo T1-S Tires, These tires are SICK, its like being on rails, wet or dry.