A friend of mine just bought 2004 doge ram ctd and the dealership cannot figure out why it will not heat up , it will get about 140* and thats it, the truck runs like total crap and bad fuel mileage. They have replaced the temp sensor and 3 thermostats and still no answer. Any ideas on what to do? They have also covered up the radiator completely and still no change. Maybe they should of bought a 6. 0 and have no problems. Any ideas will be very helpful.