so i was in the good old 91 traffic yesterday, at about 4pm...it was pretty hott out, so i had the AC on max cold, and only at the second speed (two bars). after about 30-40 mins of this, the temp guage started sky rocketing so i had to pull over and turn the car off...my wife brought me coolant (my coolant was leaking out of the overflow tube) so i put about half a container in, ran the car for about 10 mins with heat set to high and was periodically adding fluid into the reservoir. after that everything was all gravy...i didnt use the AC though, i figured it wasnt a good idea. my question is, what can i do/or check, to solve this problem? or should i just face facts and say that its a 20 year old car, its gonna happen and not run the AC in traffic? or what could have caused this?

Car background:
1992 SC400
183K miles
Auto
AC blows freakin ice cold! but for some reason theres no real in between, its either freezing cold or super hott. also, when im driving after a while with no air on heat comes through the vents, and its pretty hott, and idea about this problem too? thanks guys

 

bad thermostat not opening or blown head gasket....hope its just the thermostat, or u ran it empty and now u have air pockets in the engine...

 

I dont think its the head gasket. Otherwise id prob see those tempatures rising consistently. That was the first time it happened while using the ac. Im not getting any codes for a thermostat problem but i dont had an obd1 reader so i cant verify that

 

thermostat or Fan Clutch or low fluid. this kept happening to me in my GS300 when my Fan Clutch went out. It would also be just fine when i was going about 70 but if i slowed the car would heat up again and begin to boil or bubble into the overflow.

 

As others have said, fan clutch. Usually it can't pull enough air through the condensor to cool it off and the radiator gets heat soaked pretty bad from it.

 

Get the fan clutch fixed ASAP. If it overheats, say goodbye to your head gasket.