Not sure of the 1st gens have a bleeder, but those were my thoughts, air in the system. If a garage did the work, then they should have bled the cooling system, or at least knew it should have been done. Any time cooling system work is done, there's the potential for air to enter the system. And just like getting air in your brake lines, yup, you guessed it, its a problem. Overheating and no heat at the same time is probably the biggest symptom of air trapped in the cooling system. If you have a bleeder, then you open it until you get the air bubbles out. If you don't have a bleeder, you can do it with the radiator cap off and the engine running. Keep the radiator topped off and keep watching for air bubbles, until you don't see anymore.Rams said:Try bleeding air from system. The bleeder valve is on the thermo housing.