My friend has a 1990 Pontiac Sunbird, and its cooling system or whatever doesn't work. He says the heater core and the thermostat is fine and nobody seems to know what is wrong. The controls and the fan work ok, but it just keeps blowing cold air.
Any ideas?
2007-10-31 12:24:44 · 9 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
The feed side heater hose (going to the core) has a water flow valve which is controlled by the temp control cable. The temp control may be moving but the valve isn't opening to allow water to flow. The valve is probably frozen or clogged from years of use. No water circulating thru the core, no heat. Replace the valve and should work fine.
2007-10-31 12:32:04 · answer #1 · answered by mustanger 7 · 1⤊ 0⤋
There are a couple items to check. The first is that there is heat to the core. Put a hand on the hoses that supply the heater core, and make sure that they are both hot. If it has one or both being cold, you have a supply problem, probably the A/C max air shut off valve. The second thing is if the damper door is working. With the engine off, but after it has been running a few minutes, change the temp control setting rather fast, You should hear a clunk when the door re-adjusts. If you are not hearing the clunk, the best thing to do is to see a decent heating and air mechanic, because you would end up putting more in parts than paying for a proper diagnosis.
2007-10-31 12:34:30 · answer #2 · answered by Greg L 3 · 0⤊ 1⤋
:-) You got a little off track!
Car Heater Doesn't Work? Does the Engine Get up to Normal Operating Temp. (Reasonable Amount of time?)? If not then it is a Bad or Wrong Thermostat! (Should be 180/185 Degrees).
On the Hose that goes to the Heater Core There is a Hot Water Valve that allows Water/Coolant to flow to the Heater Core, is it working and Set right?
Thermostat and Hot Water Valve are both inexpensive and easy fixes.
SADLY "They Say" causes more problems then it fixes!
2007-10-31 13:00:28 · answer #3 · answered by sidecar0 6 · 0⤊ 0⤋
Assuming the thermostat and heater core are really alright, I would assume he is having an airflow direction problem in the heating/ventilation system. The system is vacuum controlled and if it were to loose all vacuum it would default to full heat on defrost. Since thats not whats happening, he could have a problem with an obstruction with his 'air-mix' door being stuck on full cold. That's very rare and would have to be fixed by a professional. By far a more common cause would be the thermostat that he's sure is not the problem =) Be sure his engine temperature is reaching full operating temp(190-215 deg F). 9 times out of 10, this time of year, its the thermostat.
2007-10-31 12:36:55 · answer #4 · answered by Crazy Paintballer 2 · 0⤊ 1⤋
two smaller water hoses that go into the fire wall has a
diaphram valve that is connected to the heater core, it uses the vacum from the engine to actuate, the diaphram may be defective.
You can overide the valve by simply moving it by hand, it may be stuck shut.
Its usually got a cable running to it with a wire on the inside
that pushes and pulls when heater lever is actuated, see if
its working when car is running.
2007-10-31 14:00:27 · answer #5 · answered by PENMAN 5 · 0⤊ 0⤋
You probably have air in the cooling system or your heater valve is bad.
2007-10-31 17:06:49 · answer #6 · answered by Alanrt1 4 · 0⤊ 0⤋
Sounds like the linkage is disconnected if mechanical or if pneumatic (Air Pressure and Vacuum)
operated.
Also first check the fresh air intake at the base of the windshield to see that it is not blocked by leafs etc.
2007-10-31 12:34:36 · answer #7 · answered by izzie 5 · 0⤊ 1⤋
thier is a door that opens for cooled air and shuts for hot air if something is bloking it from shuting it will blow cold air still. mice like making nest and pens fall down in the defrost vent.
2007-10-31 12:43:50 · answer #8 · answered by chad f 1 · 0⤊ 1⤋
I would check the themostat again.
2007-10-31 12:57:22 · answer #9 · answered by matthew p 2 · 1⤊ 0⤋