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07 Accord (4 cyl) - heater blowing cold

  #1  
Old 12-29-2018, 03:52 PM
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Default 07 Accord (4 cyl) - heater blowing cold

New member here, 1st post, not a mechanic. Heat blows cold - Coolant level is good, car runs at normal temp (half way btwn C an H), heater control valve/blend door (?) cable moves when temp ***** are turned from hot to cold and back.
PROBLEM (maybe?) - both hoses going through firewall to heater core (I assume) are cold to the touch when car is a operating temp and heat is on full. This seems wrong, if so, what should I do next?
 
  #2  
Old 12-30-2018, 12:25 AM
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My best guess is you might need a new heater control valve, or the old one is "stuck" closed. Not trivial to replace. But I'm no big expert. Anybody else?
 
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Old 12-30-2018, 07:39 AM
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I think the water valve is on the firewall and it should have a cable operating a lever. Key on - have someone turn the heater temperature up & down while you watch that cable moving the lever.
- Is the cable moving?
- Is the cable connected to the lever?
etc...
 
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Old 12-30-2018, 07:47 AM
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I thought he said h checked the valve and it was operating
 
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Old 12-30-2018, 03:16 PM
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The cable is connected and it moves when the temp is turned up and down. My concern is the water hoses going through the firewall. I'm assuming they're going to and from the heater core. At operating temp with the heat on high, both hoses are cold to the touch. Shouldn't at least one of of them be hot? My understanding is that hot water is sent to the heater core which is the source of the hot air coming out of the vents. Is there a water pump that pushes water into the heater core? Any help/advice is appreciated.
 
  #6  
Old 12-30-2018, 03:25 PM
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The valve is what allows the water to run through the core. If the valve is working correctly then there should be hot water running to the core. Check the temp of your upper hose is it cold also at operating temperature. Your car has one pump and if it fails you car will over heat so we know that's not the problem. I said the thermostat because your hoses are not hot. At least to the core you should have a hot hose
 

Last edited by Seanjordan20; 12-30-2018 at 03:27 PM.
  #7  
Old 12-30-2018, 03:36 PM
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Both hoses are cold at operating temp and the car has never overheated. The coolant level is good and I have had no leaks. Do you know if there's a way to test the thermostat? Also, I don't know if this matters but the car has the duel temperature (driver./passenger) feature. Both sides are blowing cold.
 
  #8  
Old 12-30-2018, 04:07 PM
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The thermostat should not cause your problem. Coolant isn't circulating through the heater core. It could be broken valve, or a clogged heater core.

Look at the hoses going into the firewall and see where you can disconnect both heater hoses at the firewall or further back. Verify the valve is working. Also try flushing water using a garden hose through the heater core. There are youtube videos on how to do this.
 
  #9  
Old 12-30-2018, 04:10 PM
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The way I test it is get a infrared thermo and see how hot the upper and lower hoses are. Other than that just pony up $10 and buy one. Lol. Your lower hose should be hotter than the upper I believe or vise versa.

If your hoses are at normal temp the valve is working correctly you may be looking at a faulty climate control which it should not be since your valve is operating
 
  #10  
Old 12-30-2018, 04:12 PM
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Originally Posted by PAhonda
The thermostat should not cause your problem. Coolant isn't circulating through the heater core. It could be broken valve, or a clogged heater core.

Look at the hoses going into the firewall and see where you can disconnect both heater hoses at the firewall or further back. Verify the valve is working. Also try flushing water using a garden hose through the heater core. There are youtube videos on how to do this.
PAhonda if he has verified that the valve is working and states the incoming hose to the core is cold (should be hot) how could it not be the stat. Just asking for knowledge.
 

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