Ok, hello and merry christmas everyone. My name is Karen and we have a 05 grand prix from hell. This is going to be long so bear with me. Started with my son in law discovering thick black gooey stuff in the radiator cap. Took it to BigO and they said it was from mixing coolants and said the system needed flushed. It had been trying to overheat and after they flushed it did ok for a brief time. It then started not having any heat and the temp gauge would go up to red line if moving in traffic but if in open air it was back down in normal range. Took it to mechanic who after us telling him what it was doing and he messed around feeling hoses and such said we never should have let BigO flush because what didnt come out was now loose and clogging the radiator and heater core. Also before I forget, we replaced 3 thermostats before taking it to him. Anyway, left the car with him and $500, a new radiator and the heater core flushed 16 times later he said it was good to go. Picked it up, no problems, heat was hot as could be. That was the only day the heat worked apparently. But wasnt aware because car isnt driven that often and weather had been comfortable without needing heat. So my daughter was driving it a few days ago and called and said the temp gauge was back up again. Hubby looked at it later and noticed antifreeze on the engine by the water pump. So we bought one and replaced it. There isnt antifreeze blowing in the motor now but still no heat and the car is overheating and I mean fast! It's only 50 degrees out today and I drove it to see if the heat would kick in. I was on interstate for maybe half mile and the gauge went up..didnt stop..right up to red line. I waited to see if it was gonna go down being in open air but it didnt, by the time I was almost home the dang thing was hootin and hollerin at me from that info center and telling me engine coolant hot. I parked it and felt the top radiator hose and it was HOTTTT. I had wondered before if it was actually getting hot because no antifreeze smell or bubbling in the engine. Apparently it is! My question is what now?? What could be causing this that we haven't already addressed? Ok, in case I didnt mention the heater is blowing hard but is cold air and no there is no antifreeze leaking into passenger floor or any other indications that I am aware of that would indicate heater core being bad. Other info on car is its an 05 has the 3800 engine and its not super charged or turbo or any of that. Any one wanna tackle this? LOL.
