i bought an 02 mdx. i drove around for about an hour so the car would be warm. i had the temp set at 90 and im still only getting cold air to blow. What could cause this?

Thanks

 

Your thermostat might stuck open or someone bypassed it

 

Your response is supposed to be a joke isn't it?

When the OP says 90 he obviously means the inside heater. Let's assume that the engine is up to normal operating temp and that the same coolant is used for the heater coil. If the engine gets up to normal temp then the thermostat is probably working. If the thermostat is stuck open then it will take a long time to get the engine warm and it may not ever get up to the correct temp. If the thermostat is stuck closed then the engine will overheat. If the heater coil has a leak then it would pee coolant out, typically in the pass wheel well, if the valve controlling the coolant flow through the heater coil is stuck closed then the heat exchange to the heater would be bypassed. Probably the heater control valve or another restriction in the path from the regular coolant path to the heater coil is my guess. Of course, the controller of the heater valve could be an issue. In the older models it is probably a control cable to a valve operated by the temp control knob/lever on the dash.