Cadillac Repair: 1996 Cadillac Seville, cold extremes, cadillac seville

Question
looking at buying this car. is there any concern about the northstar engine? warping because it is aluminum? will be used in montana with heat and cold extremes - 100 to -20 F?

Answer
Let's put it this way. I have worked on Cadillac's for over 25 years and could afford to buy one. But just do not have the time to keep fixing it and or driving my other car while the Cadillac is down waiting for major parts such as head gaskets, etc,etc,etc.