NO HEAT ? on 1998 Cadillac Catera

MY CADDY HAS NO HEAT,JUST BLOW COLD AIR. CAN YOU TELL ME WHAT THE PROBLEM IS?

Asked by for the 1998 Cadillac Catera
1 answer
The heater runs off your engine water/coolant. It's very possible that the thermostat is stuck open.The thermostat will open and close under normal conditions to keep the engine at its optimal temperature. If it stays open at all times, the water/coolant never gets hot enough to produce any heat as it goes through the heater core. The bad news is that the exact opposite can happen and it can get stuck closed and cause the car to over heat...... so my suggestion is to have it looked at as soon as possible.