Seems everyone wants to throw in Tstats without checking for the real problem. Like mentioned above. Make sure the cooling fans are coming on when they are supposed to. Also make sure the shop didn't add too much water when refilling your coolant system. I know anti freeze only raises the boiling point and NOT make any vehicle run cooler. Keep in mind water boils at 212, and most fans do not run until 232. So the cooloant boils over B4 the fans are designed to even turn on. BUT you didn't mention if it was boiling over or not. Chryslers are also a real Pain in the keester to bleed all the air out of the coolant system as well. Some shops don't even know how to bleed the air out. Hope this helps ! Lets hope they are correct in that your head gaskets are OK. The cars not worth fixing in most cases if they are.