Hey all. I am seeking a cause to an overheating issue I had. I was driving on the highway, when all of the sudden the add coolant buzzer came on and the temp. gauge needle went up past 1/2 way. I immediately pulled off the highway and turned off the motor. I then, flipped the hood up to find that the coolant reservoir tank was nearly filled up to the top with the coolant itself. So I let the car sit for around 15 minutes to cool off. I then checked the reservoir tank again, and it was near empty. So it looked like for some reason the coolant started to pour into the reservoir tank when I was driving, leaving the radiator low on level. Today, I went ahead and replaced the t-stat, seems to be running good now, even a little cooler. So can Anybody tell me what causes this issue? thanks

 

Check your radiator cap.