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Problems and Service Talk about any mechanical problems you are having

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post #1 of 13 (permalink) Old 01-09-2014, 05:13 AM Thread Starter
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Exclamation Only Blows Hot Air

I have a 2008 cobalt 2.2. When I turn on the heat it blows out very hot. When I turn it to cold it still blows out very hot heat. When I turn on my A/C still very hot air. My car temp is 185.

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post #2 of 13 (permalink) Old 01-09-2014, 05:23 AM
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You probably have a refridgerant leak.

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post #3 of 13 (permalink) Old 01-09-2014, 05:25 AM Thread Starter
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Okay so when I turn the climate control to cold and have the vents set on on for outside air to come in all I get is very hot air as if the heat is on high!

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post #4 of 13 (permalink) Old 01-09-2014, 05:35 AM
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You could try recharging the air conditioning system but if you have a leak it won't last. There also could be something wrong like a bad expansion valve. Check the easy stuff first



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post #5 of 13 (permalink) Old 01-09-2014, 05:38 AM Thread Starter
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Someone told me it could be a bad heater blend door. Dose this sound like it could be an issue?

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post #6 of 13 (permalink) Old 01-09-2014, 05:47 AM
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Could be. Should be easy to check but don't ask me how.

---------- Post added at 08:47 AM ---------- Previous post was at 08:45 AM ----------

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Originally Posted by dondiego View Post
Could be. Should be easy to check but don't ask me how.
I worked on S-10 HVAC controls but haven't had any issues with my Cobalt yet



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post #7 of 13 (permalink) Old 01-09-2014, 05:51 AM Thread Starter
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Do you known how many of these heater blend doors we have?

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post #8 of 13 (permalink) Old 01-09-2014, 06:03 AM
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Found this post searching in the forums. Maybe it will help.


Heat/Cold Blend Door
Pull the panel off right drivers side footwell. It comes off easily as it just uses spring clips to secure. There are two similar black housings with wires running to them, they are the servos for your hvac controls. The bottom one mixes heat and cold air. With the ignition on, turn the heat/cold rotary knob and see if the servo is working. If it is not, you have a servo issue: bad servo, blown fuse, wiring issue. If it is working, remove the two screws holding it in place and see if the shaft to the blend door is broken. If the shaft is broken, it will be major $$ for the dealer to fix it. Mine was broken and I didn't want to spend over a grand to have the dealer repair it. I used a piece of brass bushing with the correct i.d. to use as a coupling. Use some two part epoxy, the coupling bushing and glue the thing together in the correct position. My repair works great and it cost about ten bucks versus the $1200 the dealer wanted. Look at my post for the heater blend door repair in this section of the forum. I've added a couple pictures. They are not great but should give you an idea of what to do.

https://www.yourcobalt.com/forums/pro...alt-sport.htmlhttps://www.yourcobalt.com/forums/pro...alt-sport.html



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Last edited by dondiego; 01-09-2014 at 06:06 AM.
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post #9 of 13 (permalink) Old 01-09-2014, 06:14 AM
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I maybe some of help, got Nissan Climate controls credentials and e-609 cert to handle r12 and r134a.

The most common problem would be low refrigerant, but if its leaking, you will need to get a luminous additive and run it under UV light to scan and find where if a leak is present. If no leak is found and a/c is charged (green), then I would check next the thermal expansion valve (TXV) located inside the H block along the firewall side of your engine bay. That might be your cause. The blend air door on the control unit (under dash assembly) could be stuck in the heat setting only (door facing up). Cool air will pass through that door and enter the heater core, warming up the temp.

Another factor could be your compressor clutch gave out. If you turn on your a/c and look under your hood where the serpentine belt is, there should be a pulley with a Y shaped object sitting 1/8" inch out from it, look to see if it spins or stays solid. If it turns when you turn on a/c, your compressor clutch is working. I think we use the wobble plate type rotary compressor.

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post #10 of 13 (permalink) Old 01-09-2014, 06:20 AM Thread Starter
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Thanks I will check it out!

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