No Heat

Tiny
RDCN214
  • MEMBER
  • 2003 HONDA ACCORD
Engine Cooling problem 6 cyl Front Wheel Drive Automatic 105000 miles

Hi, I have a Honda Accord 2003 v6 and have no heat coming from the vents. The passenger side gets warm and the drivers side blow cold.

Things I have already replaced
1. Thermostat
2. Water Pump, timing belt, oil seals since I was in there
3. New Heater Core. What a job this was.
4. Upper and lower hoses
5. Heat control Valve
6. Radiator cap, and other smaller hoses that circulate antifreeze
7. Reservoir hoses

I have also flushed the system 3 times. Checked all the vent doors are opening and closing correctly. Also ordered the ATF Warmer that circulates antifreeze and warms the ATF fulid. This is on the top of transmission.

When the RPM's are rev'ed up a bit you can hear the coolant flowing in the heater core. From my research and asking questions, I was told this is AIR in the system. I was told by Honda, that when they bleed the 03 accord they lift the front of car, so the air can escape the highest point. Tried this with the car on a slope and also up on ramps, with a hose and funnel attached to the radiator ensuring the coolant is higher than the heater core. Let it run til the thermostat open about 5 times and still no heat. I feel like I tried everything on this car and have pretty much given up hope of getting heat out of the car.

I need help in getting the air out the system. There is no bleed screw on this car.

The heater hoses do heat up, but one more than the other. The hose that goes to the lower part of the heater core (the one that also has the valve) heats up more than the upper hose. The upper hose usually heats up to comparable heat when I have the engine rev'ed up to about 2500 rmp's.

Which direction would the coolant flow? Does it flow into the heater core from the bottom or the top? Bottom, being the hose with the valve on it?

One thing I forgot to mention in my initial post is that when the car is cold, like in the morning the upper and lower radiator hoses are sucked in?

Bought another radiator cap as the other one seemed like the rubber gasket was worn. I hope the new cap will resolve that, but was wondering if that would be caused by air in the system or a faulty radiator cap?
When I rev the engine I still hear the coolant flowing sound in the heater core?

After the storm in the northeast passes I will disconnect the hoses from the core and attach a garden hose to flush out both passages of the core in hopes to clear out any clogs in there.

What is the proper procedure for getting air out of the system when the car has no bleeder screw? What else can be the cause of this problem?

Service Writer, please steer me in the right direction.

Happy Holidays!
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Thursday, December 17th, 2009 AT 11:08 PM

11 Replies

Tiny
SERVICE WRITER
  • EXPERT
I found a Technical service bullitin that may help.

Turn the selector to a/c is there cold or warm air that comes out? If it is warm air, then :

SOURCE: Honda Service News

TITLE: Heater Blows Cold Air, A/C Blows Warm Air

APPLIES TO: all A/C-equipped Honda models that use a heater valve cable.

SERVICE TIP:

Got a vehicle in your shop that blows cold air from the heater or warm air from the A/C? The problem could just be the heater valve cable has slipped off the heater valve arm. There's a real easy fix for this problem. Slip the heater valve cable back onto the heater valve arm. Then cut yourself a 10 mm length of 3.5 mm vacuum hose and slide it onto the arm. This holds the cable on the arm nice and snug so it won't slip off.

Out of curiosity, are the heater hoses both hot at the firewall? Which direction would the coolant flow? It flows into the heater core from the bottom, being the hose with the valve on it.

One thing I forgot to mention in my initial post is that when the car is cold, like in the morning the upper and lower radiator hoses are sucked in?

Another radiator cap was a good idea, curious how that works out.

Check for a collasping hose from the radiator to the overflow bottle. If it isn't allowing coolant to get into the system as it cools, the air pocket may remain.
IF the system can not eliminate the pocket by drawing in coolant from the reservior the pocket can remain. I would do this first.

I agree, when you rev the engine and still hear the coolant flowing sound in the heater core, that sounds like the air pocket.

I doubt the core is clogged. You can pull the top heater hose off and start the car to see what kind of flow is there to verify.

The proper procedure for getting air out of the system on this is to leave the cap loose, (do raise the front), start the engine, allowing the cooling fan to cycle twice and close the cap.

I think you are close to nailing this. Post back as needed.
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Friday, December 18th, 2009 AT 5:19 AM
Tiny
RDCN214
  • MEMBER
Service Writer, thanks for the prompt reply. The TSB is a good one, but not the symptoms of the car.

I checked the blend door actuator and then changed it now the heater works great! Thanks for your help on this one :)
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Friday, December 18th, 2009 AT 9:18 PM
Tiny
SERVICE WRITER
  • EXPERT
Use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers, Ken
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Saturday, December 19th, 2009 AT 6:07 AM
Tiny
PROCTORDM
  • MEMBER
  • 2003 HONDA ACCORD
  • 4 CYL
  • AUTOMATIC
  • 272,000 MILES
What could cause the heat to stop working?
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
If the blower motor is functioning and blowing but no heat-check the thermostat, heater core and the air blend door/actuator
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
BLEDSOE
  • MEMBER
  • 2003 HONDA ACCORD
  • 3.0L
  • V6
  • FWD
  • AUTOMATIC
  • 172,000 MILES
No heat on passage side
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Does your car have separate left and right temp control?
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+2
Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
BLEDSOE
  • MEMBER
Yes
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
The temperature is controlled by the use of an air mix door that is operated by an electric motor/actuator. This door can be jammed or the actuator can be inoperative or have stripped plastic gears internally.
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+1
Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
ALVAFRO5353
  • MEMBER
  • 2003 HONDA ACCORD
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
I have a 2003 Honda Accord. My heater and my AC all of a sudden has stopped working. Can someone tell me what might be the problem? No air blows at all.
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
Give the blower motor housing some banging with you r hands and if the motor starts working, the brushes are running out and motor has to be replaced.
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Wednesday, December 20th, 2017 AT 6:54 PM (Merged)

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