I've searched this board and found out it's common to always have warm air blowing on your feet because of air forced past the heater core, even if you have your settings on cold.

That sure is annoying! It even gets warm on the feet with the windows down and t-tops off!

I want to cut off the coolant supply to the heater core during summer, but I DON'T want to just disconnect the hoses and butt them together. I want something like a valve shutoff that I can turn off and on by just reaching into the engine compartment. Sometimes I do need to use my heater!

Can I just stick in a plastic shut off valve on the heater core inlet line? Will that damage the water pump? Some posts seem to indicate you can just block the heater core lines and it's OK.

Should I install a heater diverter valve like on post 87 cars? How does it work, does it require a vacuum source?

Or would it be best to bypass the core and recirculate the coolant with a shunt (similar to the stock heater diverter valve)?

I'd like to just stick in a shut off valve from Home Depot. Simple, and easy to turn off and on. I just don't know if coolant HAS to flow through that part of the system.

 

Alot of the later cars came with a heater control valve. If you scour the boneyards, you can probably find a control head that has the vacuum valve to control the control valve. Look in cars from about 88 or 89 up.

I did that in my car, same deal as you complain about. I got the control head and the entire A/C wiring harness (the one that goes through the firewall below the heater core hose) nipples, which includes the extra vacuum line made into the harness. Then all you need is an in-line HCV.

 

I've heard the HCV only diverts coolant when on Max A/C? I'd like it to divert on more than just that setting.

 

I guess that depends on the control head you get...

The one I have allows coolant to flow in any "mode" selector position, but only if the temp slider is above full cold.

It does not "divert" coolant. It acts as a faucet. It either allows it to flow through the heater core, or blocks the flow.

 

Why do people call it a diverter valve then?

If it just blocks the flow, then that's all I want to do. I'll just put in a simple on/off valve on the heater core intake line. Or should I put a valve on the outgoing line too?

 

I haven't a clue. Why do people use the non-word "irregardless"? Why do they call it a "shipment" if you carry it by car and "cargo" if you carry it by ship, and so on?

I can accept no responsibility for what people call stuff wrongly. A diverter valve is a part of the AIR system, not the HVAC system. It does in fact "divert": it diverts air pumped by the smog pump from one location to another. The heater control valve does not divert, any more than the faucet on your kitchen sink does; it merely either stops or allows passage.

One valve is plenty. If the coolant can't flow into the heater core, then it can't very well flow out either, or vice-versa.

 

I know it is not supposed to allow heat to pass thru if you only have one valve on the line going to the heater core. I have a 84Z28 that I put a valve on the return side of the heater core and you would think it would stop the warm air from going into the cabin, but it doesnt. I put the valve on the entrance side of the heater core line and reversed the ends of the valve (I was told to do this by a mechanic) and it works, but you have to manually switch the valve. I plan to put a vacuum operated valve on both lines and I think that will fix the problem and allow me to swich the valve from inside the cabin.

 

Thanks for the clarification guys.

Yank,

What type of valve did you use? What material, etc.

 

The valve that I used in my car came from an early model Holden (Australian car). It works using a cable that goes from the return line of the heater core thru the firewall and hooks to the temperature control. I think they call the cable a choke cable. Like I said, I will eventually change the one valve to a valve on each line whether it is vacuum operated or 12 volt solinoid operated.