Worth it to bypass heater core?

[Dibbons]

On a non/AC car I guess hot water circulates through the heater core at all times, once the thermostat opens, right? Just wondering in the summer (or where i am nine months of the year) if it would make any difference in passenger cabin comfort to bypass the heater core altogether? Thank you.

 

[kiwigtx]

The heater can be a useful tool if you get sudden unexpected rise in engine temperatures....turn on the heater to full hot, and roll down the windows. By-passing the heater will take away that feature.
But, to temporarily bypass the heater should be fine. Usually done when the heater core is leaking. If you're worried about being cold inside the car during the colder months, the exhaust should provide some warmth from underneath....or just wear warmer clothing.
I seldom use the heater in my GTX, plenty of heat from the exhaust to warm it up.

 

[PurpleBeeper]

I think you're right and the inside of the car will be a little cooler.... unless you have headers 1/8" under the floorboard. When my heater core was leaking, I had it bypassed for several years, no problem.

 

[HT413]

It's certainly worth it if it leaks, but when the valve is off, I don't see it adding any heat to the passenger cabin?

Then again, how much do you really use the heat? I drive my car on a regular basis down near freezing temps here in NJ but never below freezing (just to avoid the road salt obviously). In all those times I've probably used my heat a handful of times, mostly just to see if it still works.

I'd agree though, in emergencies heater core can really drop the temp of an overheating engine.

 

[HT413]

I think you're right and the inside of the car will be a little cooler....

Ya think? If the valve is off, hot coolant shouldn't enter the core at all, no?

 

[eldubb440]

I installed an inline valve in my last couple cars......was very convenient

 

[Dibbons]

There is no valve on a non/AC car, that is why I was saying circulation is constant.

 

[69a100]

There is no valve on a non/AC car, that is why I was saying circulation is constant.

Only if you have the Hot/Cold lever in the H position will you have circulation through the core. Otherwise it will be cold. Think about it?

 

[HT413]

Only if you have the Hot/Cold lever in the H position will you have circulation through the core. Otherwise it will be cold. Think about it?

Yeah I gotta say the heater core has to have a valve on it controlled by the hot/cold control. Now do they inherently leak/blow by? That I don't know.

 

[Dibbons]

The heat control on a non ac does nothing with respect to coolant flow through the hoses. I just completed rebuilding the heater box and alll the temp lever does is divert air from the blower through the core or divert the air from the blower to bypass the core. The hoses do their thing regardless. Now an AC car is a different animal and includes a valve installed in one of the heater hoses.

 

[flypaper]

Only if you have the Hot/Cold lever in the H position will you have circulation through the core. Otherwise it will be cold. Think about it?

huh?
I did think about it and you totally lost me?? lol

the lever only controls a door that is inside of the heater box that
only diverts airflow and nothing more..

back to dibbons
if you have a engine that runs a little on the hot side
I would be a little hesitant as that might be the difference
from overheating or not.
otherwise go for it

 

[Ranger16]

Mine is still operable. I have no passenger comfort problems. I have used the heater on a rare evening returning from a cruise. It's an option I like having available. I'd say if it ain't broke, don't fix it.

 

[PurpleBeeper]

Ya think? If the valve is off, hot coolant shouldn't enter the core at all, no?

Well, my '70 doesn't have a heater control valve.....so yes, a little cooler. Mine always flows coolant & it's only the "trap door" that changes the air flow (non-A/C car).

 

[eldubb440]

you could totally isolate the heater core with a valve in each hose

 

[khryslerkid]

If you have a heater core in good condition, not allowing coolant to flow through it will shorten it's life. It will create more corrosion sitting idle than if coolant is allowed to flow through it. JMO

 

[BeeKool]

Just install a valve in line on the input hose.
I have several tractors with that mod. shut the valve in summer, open it other 3 seasons.

 

[eldubb440]

If you have a heater core in good condition, not allowing coolant to flow through it will shorten it's life. It will create more corrosion sitting idle than if coolant is allowed to flow through it. JMO

the core would remain full with valves on or off, no? ......... but not heat up with valves shut

 

[747mopar]

I'd just think about adding the valve. I installed a Vintage Air system that uses an electrically controlled valve that could probably be bought cheap enough, then add a hidden switch to open and close it? Coolant should sit idle in the coil but no heat if not circulating.

 

[Dibbons]

An additional valve/shutoff seems like the best idea , had not thought of that option before.

 

[khryslerkid]

the core would remain full with valves on or off, no? ......... but not heat up with valves shut

Yes and there is no circulation. After a long drive, heat can be transferred through the coolant into the core but not a lot. If you turn the fan on you might feel warmth for a moment, then it cools off again.

I'm just saying you can have a valve on one side to stop the circulation, unless your particular vehicle has a factory one that automatically shuts it off, and there is no circulation of coolant. Then it would be a good practice to open it up periodically to keep any corrosion causing sediment from clogging up the cores or worse yet corroding pin holes in the core causing a leak.

Most vehicles without a valve, rely on the dampner type door in the heater box to redirect the heat in the core from entering the cabin.