2004 Heater core bypass

[Larry B]

I’d like to bypass the heater core entirely and safely. I have a sense that it’s not as easy as just blocking the three hoses. What happens to the engine when this flow is cut off?
Thank you.

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[j&d]

I think the best thing to do is pull the 3 hoses off the heater core and tee them together. Then the flow could still occur but not through the heater coil. Make sense?

 

[JoseG]

There may be room back there to use a dual heater control valve like the one that comes with the car, I believe there are two 5/8 hoses and one 3/4 hose with the valve disconnect there should be constant flow or you can find a T connector in 5/8 and 3/4.

 

[sscharfman]

I’d like to bypass the heater core entirely and safely. I have a sense that it’s not as easy as just blocking the three hoses. What happens to the engine when this flow is cut off?
Thank you.

The dual heater control valve completely shuts the coolant flow to the heater when the controller tells it to. I've taken mine apart, that's what it does. Nothing should happen to the engine if you make that a permanent situation by clamping the hoses or any other way.

 

[JoseG]

The dual heater control valve completely shuts the coolant flow to the heater when the controller tells it to. I've taken mine apart, that's what it does. Nothing should happen to the engine if you make that a permanent situation by clamping the hoses or any other way.

One of the pipe and hose leading to the heater core makes a Y and go from the degas bottle to the dual control valve.

 

[Larry B]

The heater core is fully ‘on’ overpowering the A/C. Replacing the DCV may not be a long term fix, but will be tried when funds allow. Blocking the hoses is the back up fix.

 

[74 Harley]

Is it the dcv, or the blend door that controls airflow?

 

[Larry B]

The blend door controls airflow, but since I’m having trouble paying for replacing the DCV, I can’t see affording to fix a blend door.

 

[Bigdog1949]

I’d like to bypass the heater core entirely and safely. I have a sense that it’s not as easy as just blocking the three hoses. What happens to the engine when this flow is cut off?
Thank you.

Causes more problems ,I tried it ,was boiling over in the fill bottle !

 

[Larry B]

Thank you. I had a new DCV put in and it’s working fine now.

 

[hydroplaneu3]

Has anyone successfully bypassed the heater core?

 

[tmcafee52]

I have the same question about the best way to bypass the heater core on a 2005. I'm pretty sure that the heater core is leaking. The heater core is divided into sections with 2 inlet hoses and an outlet hose so the typical heater core bypass kit where you connect the input to the output hose won't work. I saw that someone suggested a Tee. Does anyone know the inner dimensions of the 3 hoses going to the heater core?

 

[JoseG]

I have the same question about the best way to bypass the heater core on a 2005. I'm pretty sure that the heater core is leaking. The heater core is divided into sections with 2 inlet hoses and an outlet hose so the typical heater core bypass kit where you connect the input to the output hose won't work. I saw that someone suggested a Tee. Does anyone know the inner dimensions of the 3 hoses going to the heater core?

I believe 2 of them are 5/8 and the other one is 3/4.

 

[hydroplaneu3]

I have the same question about the best way to bypass the heater core on a 2005. I'm pretty sure that the heater core is leaking. The heater core is divided into sections with 2 inlet hoses and an outlet hose so the typical heater core bypass kit where you connect the input to the output hose won't work. I saw that someone suggested a Tee. Does anyone know the inner dimensions of the 3 hoses going to the heater core?

What I thought was a leaking heater core turned out to be a cracked coolant hose flange. I have looked repeatedly just in case it was under the hood but saw no steam. I couldn't find it and finally it let go and my mechanic found it.

 

[tmcafee52]

What I thought was a leaking heater core turned out to be a cracked coolant hose flange. I have looked repeatedly just in case it was under the hood but saw no steam. I couldn't find it and finally it let go and my mechanic found it.

I'm starting to think that the leak might be coming from the coolant overflow hose next to the firewall instead of the heater core. I haven't noticed any moisture inside the car when the leak occurs. It is coming from behind the engine block. If the heater core is leaking, should I be able to see the leak or some moisture inside the car?

 

[JoseG]

Check the coolant reservoir plastic tank for cracks also the plastic housing under the intake manifold and the throttle body hose.
The heater core will usually leak by the ac evaporator drain.