when you put a shutoff valve on the hot hose to the heater, how does the coolant complete it's cycle around the block

 

It doesn't. There is no coolant flow
in the heater hose lines it just sits there

 

This illustration should help visualizing it.

 

I was worried that it might need to circulate but mine stays shut off most of the time and it holds 180.

 

It is probably just me, but I always let a bit of coolant flow thru the heater core every few weeks or so.............just to keep coolant fresh in the heater and not stagnant. Somewhere in my old memory, having stagnant fluid/coolant locked into a heater core is not good long term. Occasional flow thru the heater keeps everything consistent..

Probably the most important thing though is maintaining fresh coolant in the system and not letting it deteriorate/degrade over extended time.

Larry

 

So you could remove and cap off both heater hoses and there would be no ill effect on coolant flow

 

Correct.

Larry

EDIT: If you have a small block car with an expansion tank, the expansion tank must be kept in the cooling system for everything to work correctly.

 

With one shut off valve, I would expect the coolant to remain warm if not hot due to convection even thought there is no flow. I have only one valve at the intake, but am considering adding another valve at the firewall or near the expansion tank. My guess, may be wrong.
Ron

 

I don't see how a second shut off valve would stop heat by convection. Heat will pass through the valve just like it does the other one. It will stop hot coolant from flowing through the heater box though. If that's what you're trying to avoid pull the two hoses and connect them together the water will still circulate but bypass the heater box.

 

True, , and the fact that the hoses run less than 2 in. above the exhaust manifold may negate any benefit of stopping the flow to the heater valve. I have never tried to check the temp of the air inside with the engine at NOT and the valve closed. Could be a total waste of time and money. The loop to totally bypass the heater core seems to be the answer or just plug the hose fitting at the intake and remove the T from the hose to the expansion tank. It is a win / win modification except for the noise from the passenger's seat when we go out and the temperature is below 70F. It can drown out the exhaust tunes.

Also in my racing days, I used the heater to help cool down the engine on the return road and in the pits between rounds. It came in handy when cruising in town on a hot day also as the engine compartment of the Vega was even tighter than a C2.

 

point taken R66 my idea was to remove hoses altogether and cap oat water pump and thermostat so no hoses close to headers

 

And you double the space to get the the spark plugs. That may be the best thing if you live in a 70F or above climate.

 

When I was building my 65 coupe, I tried another method to keep heat out of the interior. Instead of a shutoff valve for the core, I insulated the inside of the heater box where the core sits. I had some leftover foil backed heat insulation that was thin enough to line the box without getting in the way of the air flow to the heating ducts. So far, it has worked great. The heater still works as usual and I don't get heat inside the car when the fan is turned off. I realize that it is a real pain to pull the heater box, but if you happen to have it out for something else, it is an easy job and it solves the problem. I have never liked the look of a valve under the hood and this method still circulates the coolant.

 

think i'm going to go with removing hoses and capping off all outlet and inlets it will clean up the engine bay and open up access to plugs etc as R66 said car is only driven in warm weather so not concerned about having to need heat

 

Don't forget to include the expansion tank in your modified cooling system....if you have a small block car. It is needed with the factory aluminum radiator. See Post #7

Larry

 

If you do decide to completely remove the heater hoses from your heater core, Inline Tube makes a nifty set of rubber caps for the ends of the heater core. I completely removed both of my hoses (67 BB) and used these black rubber caps.

They fit perfectly and made the job easier. Make sure to take a high pressure air hose and blow out all of the remaining coolant from your heater core before you cap it off. C.J.

https://www.inlinetube.com/products/inl10827

 

You guys keep me up at night THINKIN'.
The heater core is brass / copper and these materials oxidize when exposed to air, although it should not be a fast deterioration of the metal, it will happen.
I am thinking one may want to drain the heater core and put an inert gas or liquid (e.g., argon or fresh antifreeze) in the heater core to preserve it while capped off. Of course some may never plan on restoring the heater core to operation, but some may. Of course this would then require a leakproof plug like a plumber's test plug.
Are there any metallurgists out there that could provide guidance on storage of the heater core?
Also, if you cap or valve off both hoses and drain the heater core and hoses but leave them in place, the hoses are still subjected to the heat of the exhaust manifold and thus the rubber may deteriorate without the coolant in the hose.
Ron

 

Thanks R66 no problem with the hoses they are going to be removed and all fittings capped like C2Scho indicated

 

question for C2Scho when you removed to hoses did it in fact affect the heat in the cockpit

 

Yes, it could be psychological but it seemed to make the cockpit cooler. My wife commented that her legs felt cooler on those hot summer drives.

The two main reasons that I did it were for extra room along the passenger side of my engine, and to never again experience a broken/split heater core. I distinctly remember driving along on a beautiful spring day south of Mt. Vernon and looking over in shock as I watched my passenger side foot well slowly fill up with green Anti Freeze/Coolant until there was more than an inch sloshing around there. I kept thinking about the brand new Al Knoch carpet that I had just installed. Fortunately I was single with no wife or girlfriend (at the time) and no one to freak out with hot coolant at their feet. Taking out a bad heater core and installing a new one is not a fun job on a C2 and so I vowed never again. The only thing that I ever used my heat for was to help cool down the engine. I never drive my car on cold days or in inclement weather. Ever.

My wife was none too pleased on a 96 degree summer day with the sun beating down (convertible) on us and I reach over to turn the heat on full blast as the temp needle heads north of 220, I will say that it helped to cool down the engine but those days are gone; and no more using the heater core to cool down my engine. My heater core has been blown out using compressed air with no coolant remaining and capped off since October of 2018 and I have never missed having heat in the cockpit. C.J.