Heater blowing cold air
 

Can anyone please give me some advice. I have a 1994 Z28 that i have owned for 5 months. Car runs great. However I noticed last week that I have no heat coming thru my vents. A new thermostat was instaled 3 months ago. Temperture of air never changes, regardless of how hot the engine is///please help winter is near!!

RE: Heater blowing cold air
 

ill see if i can help, if u open ur hood, look to the left of the engine. u will see two rubber hoses heading to the firewall of the car. one attached to the water pump, and one goes somewhere else. for some reason, radiator fluid may be going in one, but not coming out the other, or vis versa. its kindof hard to think of a solution because of ur new thermostat. maybe its a dud. test ur radiator flow by simply leaving the radiator cap open, and running the car until the thermostat opens, should be somewherre around 180 degrees F. if radiator fluid is not freely flowing the the radiator, then that could be a water pump problem. hope i can be of help.

RE: Heater blowing cold air
 

simply, u may have a worn water pump

RE: Heater blowing cold air
 

Warm up your engine and race the engine (around 2000 RPM) and feel the hoses going to the heater, they both should be hot. If they are cold, the heater core is clogged. If they are hot then check the temp control & verify that the control cable is attached and moving the door that directs air to the heater. You should hear the heater door make noise as it opens and closes. There is also a possibility that the heater was disconnected for some strange reason. Does the defroster blow hot air??

Also, the thermostat is not involved with the heater, it only controls the flow of water to the radiator. When the thermostat is closed water for the heater bypasses the thermostat. This is done so that heat is available quickly.

RE: Heater blowing cold air
 

yes, but if the thermostat does not open, then how does hot radiator fluid make it to the heater?

RE: Heater blowing cold air
 

it is heater core

RE: Heater blowing cold air
 

When the thermostat is closed, water for the heater circulates from the water jacked to the heater core bypassing the radiator. Hard to explain without a cooling & heating system diagram.