Heater Problems

[danrstuart]

So my heater is blowing cold air. I replaced the thermostat and all the coolant in the system but still no luck. Does anybody have any other tips or things i could check to fix this?

Thanks for your help

 

[u812many73]

There is a valve under the dash that controls the fluid flow from the engine cooling system to the heater core inside the car. When you turn the temp control on the AC unit it opens or closes this valve with a cable running from the control to the valve, if its not hooked on properly this may prevent the heater from getting adequate flow from the motor. I'm not sure which one it is though, there is a cable for the heater's valve, and one for the floor/dash/defrost vent selector too. If I'm not mistaken you can access both by removing the glovebox, one is right behind it, the other is more centered in the dash. I would drop the glovebox and take a look at these cables. They should both move an actuator at the end of the cable when you turn the control knobs, if either one isn't hooked up or hooked up improperly that could be your problem. Hope its as simple as that. Good luck!

 

[CheeseHelmet]

Along with what u812many73 said, there are three other things I can think of that might cause your heater to stop working.

1. Air in the coolant lines. This happened on my bother's car, the engine would run fine (ie. no overheating) but you'd get no heat in the car (quite problematic during the winter ). We ended up adding coolant to the rad with the engine running which solved the problem. I didn't run into this problem when I changed my coolant so YMMV.
2. Clogged heater core. Less likely, but you never know. Does you overflow can have rust flakes or other crap in it?
3. Stuck thermostat. Way less likely, if this was the problem you'd notice your car would overheat on long trips.

 

[P-Funk!]

Most often with the P5 it is the door not hooked up. It is easy to knock off when doing any work (replacing a radio fr'instance) in that area...

 

[Dougreig]

There is a valve under the dash that controls the fluid flow from the engine cooling system to the heater core inside the car. When you turn the temp control on the AC unit it opens or closes this valve with a cable running from the control to the valve, if its not hooked on properly this may prevent the heater from getting adequate flow from the motor. I'm not sure which one it is though, there is a cable for the heater's valve, and one for the floor/dash/defrost vent selector too. If I'm not mistaken you can access both by removing the glovebox, one is right behind it, the other is more centered in the dash. I would drop the glovebox and take a look at these cables. They should both move an actuator at the end of the cable when you turn the control knobs, if either one isn't hooked up or hooked up improperly that could be your problem. Hope its as simple as that. Good luck!

 

[Dougreig]

Thanks u812many73. You saved me a some service garage cost. The retainer clip that secures the cable for temperature control was not attached the securing bracket. Thanks again