If it's older then 2008 stay the fuck away. The Northstar motors in the older models WILL blow a head gasket, they did a redesign around 2006, I think, that took care of that issue. If you blow a headgasket the motor has to come out, through the bottom of the car, to get fixed... If it even can be fixed, usually they need a full rebuild. You're looking at a few grand for just a headgasket job done right, closer to 8-9000 if it needs a basic rebuild. My father had a 99 that we kept pouring bottles of head gasket sealer just to keep it running, I would've burned the fucking thing if it was mine. I fucking love Cadillacs, but you couldn't give me one that's fwd with a Northstar motor. I had a 2009 DTS level 4+, every available option except for power window curtains. It was a nice car, but i started having issues with the HID headlamps and a JUNKYARD replacement was going to be around $800 for ONE headlight assembly. I unloaded that thing quick. If you want a caddy look for one with a LS based motor or the DI V6 and still be prepared to pay Cadillac prices for repairs.
yea i was reading about the northstar people were posting "NOT NORTHSTAR" then i read on like car shows how some people will convert the motors cause it was northstar and how people frown upon that cause they are not greatful for what the car had in it originally i guess this is mostly for people that claim "stock" at car shows. i was just looking at it for fun remembered about that brand as i usually dont looking into caddy's in general but i seen how cheap and low mileage they were so i got excited until i started to do a little more research. likely gonna stay away from it on this website i looked up says it was #3 in cost of maintenance in a 10 year span off the lot i suppose.