[4th Gen : 01-07]: 2.4L No Heat. Top hose hot bottom hose cold
#1
01-27-2019, 01:27 PM
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2.4L No Heat. Top hose hot bottom hose cold
2002 Dodge Caravan 2.4L 4Cyl No Heat 264,000 miles. New Radiator. Coolant flushed. Engine temp 1/2 way as it should be. Hoses warm. Antifreeze filled. Top heater hose to core on firewall is warm bottom hose is cold. I removed the glove box and removed the actuator motor from the bottom 2 phillips screws. The motor has a male star pattern which fits into the female. I thought this was only for internal air or external air. On line they keep calling this the heat actuator. Does not seem as if this controls the flow of antifreeze. Even if I turn the female star pattern cylinder in the bottom of the fan motor in both directions I do not get any heat regardless. When I turn the dial on the dash from cold to hot I hear a difference in sound as if something changes. Hard to see anything else. What should I do next? THANK YOU!
#2
01-27-2019, 03:00 PM
the actuator controls air flow blend doors....nothing to do with coolant flow. coolant should be flowing thru the heat core at all times...the blend doors decide if blower motor air bypasses or go thru the heater core. So either the blend door isn't directing air flow or the heater core is plugged. If you had heat at high rpms but not at idle...you may have air in the heater core
sounds like you make have a blocked heater core. a good core should have 10*C temp drop thru it.
check for blockages by removing both hoses at the fire wall and check its flow with a garden hose.
sounds like you make have a blocked heater core. a good core should have 10*C temp drop thru it.
check for blockages by removing both hoses at the fire wall and check its flow with a garden hose.
#3
02-04-2019, 03:43 PM
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Heat issue 2002 2.4L EC Caravan
Not heat. I removed the bottom inflow and top out flow hoses on the fire wall. Since it is too cold to run a garden hose here I used an air tank It blew out all of the antifreeze through the core. Air is flowing freely regardless of which hose barb I blow air into top or bottom. I have to assume now the core is not blocked. The actuator at the bottom of the blower motor works fine. This is activated by the recirculation button on the dash and does not control the heat. This controls air circulation inside or outside the cabin. The A/C blows cold and the compressor kicks in. Both A/c and heat will not generate any hot air. The antifreeze is filled to the proper level. Is there a heater control valve and can someone tell me where it is located? This sounds like it could be the issue. When I turn the manual dash dial from cold to hot there is a change in sound from the airflow. But again no heat. I also tried and went through the calibration test and the light never stopped blinking. Temperature gauge is in the middle. No overheating issues. Any suggestions are appreciated.
#4
02-09-2019, 03:39 AM
there is no heater control valve. the hvac case has 3 acutators...one for recirculation...one for mode..ie defrost/vent/floor and one for temperature blending...find the one that moves with the heat control and make sure its moving the door.
if the flashing doesn't stop...the calibration isn't completing...maybe due to a failed actuator or broken blend door/blocked blend door. the system is smart...check for codes in the hvac module
if the flashing doesn't stop...the calibration isn't completing...maybe due to a failed actuator or broken blend door/blocked blend door. the system is smart...check for codes in the hvac module
#5
03-11-2019, 06:30 PM
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2002 Caravan EC no heat, all 3 actuators working
Finally a decent day. Took apart the bottom dash and removed all 3 actuators. They all work. Manually opened and closed the blend door and still no heat. I have recirculation, + air flow adjustment from the top, bottom. The top heater hose is hot bottom is cold on the fire wall. As stated I do not have access to a hose but did blow it out with an air compressor. Anything else I can check? Is is possible my water pump is not pumping antifreeze through? Van does not run hot at all. Thanks much! JRR
#6
03-11-2019, 08:43 PM
#7
03-11-2019, 09:20 PM
The heater core will only heat the air as much as it has hot surface area available. These numbers aren’t fully accurate but they demonstrate my point -
100% hot surface area = 100% heated air
90% hot surface area = 90% heated air
80% hot surface area = 80% heated air
And so on...
Heating the air creates a temperature drop between the inlet and outlet but at any time a fully warmed engine should result in both hoses being relatively hot at all times if flow thru the heater core is sufficient. If either of the hoses for the heater core are cold then lack of flow due to a blockage in either the heater core or a hose is indicated.
The reason you could blow air thru it with no problem is because air has no mass and will push thru every crack and opening it finds. Water does have mass and will not flow as freely thru a plugged heater core. To confirm this, remove the bottom hose at the firewall and plug it.
Set the heat to vent, full hot and full blower speed. Start the engine and observe flow out of the heater core - if it’s anything less than free flow then the heater core is plugged or partially blocked.
If it’s free flowing, hook up the hose to the heater core and unhook it from the engine. Again you want to plug off the engine side somehow, then run the engine and observe flow out of the hose. Less than free flow means the hose is plugged or partially blocked.
100% hot surface area = 100% heated air
90% hot surface area = 90% heated air
80% hot surface area = 80% heated air
And so on...
Heating the air creates a temperature drop between the inlet and outlet but at any time a fully warmed engine should result in both hoses being relatively hot at all times if flow thru the heater core is sufficient. If either of the hoses for the heater core are cold then lack of flow due to a blockage in either the heater core or a hose is indicated.
The reason you could blow air thru it with no problem is because air has no mass and will push thru every crack and opening it finds. Water does have mass and will not flow as freely thru a plugged heater core. To confirm this, remove the bottom hose at the firewall and plug it.
Set the heat to vent, full hot and full blower speed. Start the engine and observe flow out of the heater core - if it’s anything less than free flow then the heater core is plugged or partially blocked.
If it’s free flowing, hook up the hose to the heater core and unhook it from the engine. Again you want to plug off the engine side somehow, then run the engine and observe flow out of the hose. Less than free flow means the hose is plugged or partially blocked.
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#8
04-17-2019, 08:38 AM
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