Overheating Problems 96 Regal Custom

I have a 96 Buick Regal Custom with 3.1L V6 (208,124 Miles). Yesterday while driving on the highway the temp gauge was at 1/4 of the way up. As I was coming to a stop the car stalled, restarted idle rough for a few seconds leveled out. Next stop it stalled again, wouldn't restart, noticed temp gauge was pegged out. For the past few months it has been losing coolant. No visible leaks on the ground or on any of the hoses or water pump. Last month I changed the radiator cap, thermostat, and belt tensioner. Checked the oil, nothing strange, pulled 1 spark plug, nothing strange. The water pump bearings are making some noise but still spins freely. It does not overheat when at idle just when I drive for a while on the highway and come to a stop, the temp gauge goes from 1/4 to pegged in a matter of milliseconds. Any ideas?

Welcome to AF!!

Based on your description it sounds like you may have a multitude of issues. The fact that you were losing coolant indicates that you have a leak somewhere. It could be the water pump weeping and dropping coolant so slowly that you are not seeing it. If the bearing is noisy, I would change it. I would also change the thermostat since it seems like it is not opening properly causing coolant not to circulate. You also should check the fans to make sure they are coming on at the proper time. If they are not running that may be why the car is overheating.

One problem exists however, since the car overheated to the point where it wouldn't restart you may have head gasket issues when you start working on it. Do a compression check to see if anything has warped before putting a lot of time and money into repairing this engine. Good Luck!