I have a 96 Lumina that has had an intermittent problem with the low coolant light coming on. Especially when going around a corner!?!? We add about a half of cup of coolant and the light goes off. However in the last week or so the low coolant light comes on more often and once in while the temp gauge starts climbing up to the red very quickly but then seems to go right back down to where it should be. the heat works great sometimes and then all of a sudden no heat. Last night when I was coming home from work the temp gauge was where it should be but no heat and all of a sudden the temp gauge spiked all the way to the red and then a red heat warning light came on. I pulled the car over. let it cool off and then started it, the temp gauge went promptly back to where it should be and I managed to make it home. It seems like the old days (1970's) when I would have a sticking thermostat problem, replace the thermastat and all was well. however reading some of these forums I'm concerned it may be something more serious. My husband is a good back yard mechanic so I'm hoping it is something he can fix.