2005 BUICK RENDEZVOUS Unknown Or Other Problems

I bought my car from a used car lot. I had it about 3-4 months and out of the blue it overheated very quickly, the warning light was on, some type of loud buzzer was going off so I pulled over and let it cool off, it took about 45 minutes but it started back up. I checked all the fluids and coolant levels and everything was ok. This continued to happen for about 3 weeks, quickly overheat, lights, alarms pulled over, checked fluids over and over. After about 3 weeks it would quickly overheat and then shut off on its own and several times it happened so fast I barely got off the road.i took it to a mechanic that drove it around a little until it overheated which at this point only took about 3 minutes to happen. He said there was air in my radiator and he...

SPEED GAUGE DOES NOT WORK PROPERLY CAR RUNS BOILING HOT WHILE TEMP GAUGE SAYS IT'S COOL, FUEL GUAGE GOES OUT LIKE I'M DUMPING FUEL ON THE INTERSTATE AT HIGH SPEED,CAR SHUTS OFF, SO DANGEROUS, YOU NEVER KNOW WHEN IT WILL HAPPEN.

HAVE HAD TO REPLACE HEAD CASKETS TWO TIMES SINCE I BOUGHT THIS NOW HAVING PROBLEMS WITH GAS SMELL WHEN I TURN ON HEATER WHATS NEXT ITS GOT ABOUT 51000 MILES ON IT

WE FOUND OUT THAT WE HAD A PROBLEM WITH MY WIFE'S VEHICLE. INITIALLY, THE VEHICLE WAS STATIONARY. I TOOK IT TO GET AN OIL CHANGE AND WAS ASKED TO COME INTO THE SHOP TO BE SHOWN THAT THE ANTIFREEZE WAS LIKE YOGURT IN THE RESERVOIR. WE WERE TOLD THAT WE NEEDED A COOLANT FLUSH. THIS LED TO BEING TOLD THAT WE NEEDED A NEW RADIATOR; BYPASS HOSE; AND LAST BUT NOT LEAST, HEAD GASKET JOB AMOUNTING TO APPROXIMATELY 1600.00. WE WERE TOLD THAT THERE WAS NO OPEN RECALL BUT YET THERE WAS LITIGATION GOING ON REGARDING DEX-COOL ANTIFREEZE AND THAT IT WAS CAUSING ALL OF THE PROBLEMS THAT WERE AND ARE HAVING WITH THIS VEHICLE.