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Like when the a.c. is o does cools t still flow through it? Or does the vent controller just switch it so it takes in cold air? I forget the name, sorry.
Does coolant flow through the heater core all the time?
- Thread starter The motor guy
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Depends on the car.
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On the truck in my sig.
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Or any vehicle in general. What's the most common setup?
Follow your heater hoses, if there is a control valve in one of the hoses it does not flow all the time. No heater control valve...then it flows all the time through the heater core.
If the vehicle has a heater control valve on the heater hoses, then no. If it does not have a heater control valve then there is always coolant running through the heater core.
Sorry but a thermostat in almost any vehicle directs water from the engine through the heater core from the second you start it, even if completely cold. I am sure the overwhelming majority of cars and trucks have a central divider in the AC plenum to allow air to flow over the heater core or not, commonly called a blend door.
Originally Posted by SteveSRT8
Sorry but a thermostat in almost any vehicle directs water from the engine through the heater core from the second you start it, even if completely cold. I am sure the overwhelming majority of cars and trucks have a central divider in the AC plenum to allow air to flow over the heater core or not, commonly called a blend door.
Exactly. In virtually every modern car coolant circulates through the heater core 100% of the time- interior air temperature is set by one or more blend doors in the HVAC ducting.
Sorry but a thermostat in almost any vehicle directs water from the engine through the heater core from the second you start it, even if completely cold. I am sure the overwhelming majority of cars and trucks have a central divider in the AC plenum to allow air to flow over the heater core or not, commonly called a blend door.
Exactly. In virtually every modern car coolant circulates through the heater core 100% of the time- interior air temperature is set by one or more blend doors in the HVAC ducting.
I know on later model Ram 1500 pickups, they have a coolant 3-way valve that sends coolant to the heater core, transmission fluid heater or both, depending on how you have the HVAC controls set. Yet another wonderful component that will set a code when it malfunctions.
Originally Posted by another Todd
Follow your heater hoses, if there is a control valve in one of the hoses it does not flow all the time. No heater control valve...then it flows all the time through the heater core.
^This! If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door and save undue stress on the heater core in the summer.
Many types are available manual, vacuum and electric some even with a rheostat.
Follow your heater hoses, if there is a control valve in one of the hoses it does not flow all the time. No heater control valve...then it flows all the time through the heater core.
^This! If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door and save undue stress on the heater core in the summer.
Many types are available manual, vacuum and electric some even with a rheostat.
Originally Posted by Trav
... If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door ...
Hmm... I wonder if lack of a shut-off valve, a leaky blend door, or some other form of heat leakage might be why my Prius blows warmer than outdoor air when heat and AC are both supposed to be off. It's very annoying in mild weather. My brother has the same complaint with his '95 Avalon. My Mazda had a proper coolant shut-off valve AND blend-door temperature control.
... If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door ...
Hmm... I wonder if lack of a shut-off valve, a leaky blend door, or some other form of heat leakage might be why my Prius blows warmer than outdoor air when heat and AC are both supposed to be off. It's very annoying in mild weather. My brother has the same complaint with his '95 Avalon. My Mazda had a proper coolant shut-off valve AND blend-door temperature control.
Originally Posted by CR94
Originally Posted by Trav
... If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door ...
Hmm... I wonder if lack of a shut-off valve, a leaky blend door, or some other form of heat leakage might be why my Prius blows warmer than outdoor air when heat and AC are both supposed to be off. It's very annoying in mild weather. My brother has the same complaint with his '95 Avalon. My Mazda had a proper coolant shut-off valve AND blend-door temperature control.
Quite possible. The easy way to tell is use a thermometer in the vent on full A/C, disconnect the heater core and put a connector in between the 2 hoses (or a piece of hose to the 2 block connections) so you can run the engine, if the temp at the vent drops you have your answer.
Install a valve before the core.
Originally Posted by Trav
... If it doesn't have what was commonly referred to as a Ranco valve you can fit one easily, it will improve A/C performance on older cars that may have a leaky blend door ...
Hmm... I wonder if lack of a shut-off valve, a leaky blend door, or some other form of heat leakage might be why my Prius blows warmer than outdoor air when heat and AC are both supposed to be off. It's very annoying in mild weather. My brother has the same complaint with his '95 Avalon. My Mazda had a proper coolant shut-off valve AND blend-door temperature control.
Quite possible. The easy way to tell is use a thermometer in the vent on full A/C, disconnect the heater core and put a connector in between the 2 hoses (or a piece of hose to the 2 block connections) so you can run the engine, if the temp at the vent drops you have your answer.
Install a valve before the core.
Not all valves leak. I can tell you for certain that I've encountered some that will not leak a drop through when closed.
Originally Posted by JTK
I know on later model Ram 1500 pickups, ..... Yet another wonderful component that will set a code when it malfunctions.
ONLY if you buy a Dodge/Ram.
I know on later model Ram 1500 pickups, ..... Yet another wonderful component that will set a code when it malfunctions.
ONLY if you buy a Dodge/Ram.
Depends on the vehicle. Some have vacuum actuated valves to close off the coolant flow, some use electronic valves, some leave it flowing through the core all the time. It can also depend on whether the vehicle has dual / tri climate zones or not. There is no standard answer that fits all vehicles.
That said I'm a fan of it flowing through the core all the time. IMO these systems don't plug up the heater cores as often where the coolant it shut down through the core, say all summer long sort of thing.
That said I'm a fan of it flowing through the core all the time. IMO these systems don't plug up the heater cores as often where the coolant it shut down through the core, say all summer long sort of thing.
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Mine has three. Fan speed/temp/vent position if that's what you're talking about.
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