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Hello, I have a 99 Cirrus (2.5 V6) that put out great heat until this season, so I'm thinking heater core would not suddenly go bad. I have flushed out system, installed all new hoses, quality thermostat, new coolant. Engine temp gage is in normal range. I was able to check lever operation controlled of cold to hot rotary switch and can see one blend door toward drivers side working properly. How do I see that other blend doors are working? Or does anyone have any other suggestions? I'll be needing heat soon! Thanks Mopar People! Jim
 

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Hello, I have a 99 Cirrus (2.5 V6) that put out great heat until this season, so I'm thinking heater core would not suddenly go bad. I have flushed out system, installed all new hoses, quality thermostat, new coolant. Engine temp gage is in normal range. I was able to check lever operation controlled of cold to hot rotary switch and can see one blend door toward drivers side working properly. How do I see that other blend doors are working? Or does anyone have any other suggestions? I'll be needing heat soon! Thanks Mopar People! Jim
 

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. . . I have a 99 Cirrus (2.5 V6) that put out great heat until this season, so I'm thinking heater core would not suddenly go bad. I have flushed out system, installed all new hoses, quality thermostat, new coolant. Engine temp gage is in normal range. I was able to check lever operation controlled of cold to hot rotary switch and can see one blend door toward drivers side working properly. How do I see that other blend doors are working? . . . .
The temperature blend door is mechanically actuated by the rotary temperature knob on the HVAC control panel. If you see the lever arm move and rotate the door when you twist the knob then that part is working properly. Only other possibility is that the heater core is partially plugged and not allowing proper circulation.

Feel the inlet and outlet hoses at the firewall in the engine compartment with the engine at operating temperature. Both should be hot to the touch. If one is hot and the other cold or lukewarm, then the heater core is corroded and plugged. If that is the situation you could try a reverse flush just at the heater core lines at the firewall and see if that dislodges any debris and gets flow through the core. Otherwise you will need to replace the heater core. The heater core can be accessed under the dash and without having to remove the HVAC plenum box.
 

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With the engine cold, the level of coolant under the radiator cap should be right up to the top. If it is not, there are 2 suspects. The filler tube seat where the radiator cap sets is corroded/pitted (common problem) and does not allow the coolant to be pulled back from the reservoir into the engine when cooling. The hose from the filler tube over to the reservoir either is not sealing at the ends or has a crack/split that prevents the coolant from being pulled back from the reservoir. With the coolant level not at the top when cold allows for an air bubble in the system which seeks out the heater core.

If your filler tube is corroded/pitted. I suggest replacing it and also replacing the radiator cap as the pitting on the filler tube seat will have damaged the radiator cap seal. You can find the filler tube on Rockauto. I had a '97 Sebring convertible 2.5l and replaced the filler tube every 3 years or so due to the pitting.
 

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Discussion Starter #5
The temperature blend door is mechanically actuated by the rotary temperature knob on the HVAC control panel. If you see the lever arm move and rotate the door when you twist the knob then that part is working properly. Only other possibility is that the heater core is partially plugged and not allowing proper circulation.

Feel the inlet and outlet hoses at the firewall in the engine compartment with the engine at operating temperature. Both should be hot to the touch. If one is hot and the other cold or lukewarm, then the heater core is corroded and plugged. If that is the situation you could try a reverse flush just at the heater core lines at the firewall and see if that dislodges any debris and gets flow through the core. Otherwise you will need to replace the heater core. The heater core can be accessed under the dash and without having to remove the HVAC plenum box.
THANKS ALLEN.
 

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Discussion Starter #6
With the engine cold, the level of coolant under the radiator cap should be right up to the top. If it is not, there are 2 suspects. The filler tube seat where the radiator cap sets is corroded/pitted (common problem) and does not allow the coolant to be pulled back from the reservoir into the engine when cooling. The hose from the filler tube over to the reservoir either is not sealing at the ends or has a crack/split that prevents the coolant from being pulled back from the reservoir. With the coolant level not at the top when cold allows for an air bubble in the system which seeks out the heater core.

If your filler tube is corroded/pitted. I suggest replacing it and also replacing the radiator cap as the pitting on the filler tube seat will have damaged the radiator cap seal. You can find the filler tube on Rockauto. I had a '97 Sebring convertible 2.5l and replaced the filler tube every 3 years or so due to the pitting.
THANKS GERRY.
 
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