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Heater Hoses Plugged


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My heater valve on my 71 was so bad that I plugged each of the 2 hoses that go through the fire wall (I don't need heat in Virginia). My question is..... Is blocking them off OK or should I connect the two with a tube so the water continues through the hoses and back into the engine? Is it better one way or the other as far as engine cooling is concerned?

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Plug them. Connecting them short circuits the head cooling system. This has been discussed at length here and on hybridz.

This didn't make perfect sense to me initially, since doesn't having the heater on produce the same short circuit? Well yes and no! The heater valve and the heater core are a significant restriction compared to a wide open 5/8 heater hose, AND more importantly when the heater core is loosing heat it is helping the overall cooling process.

Its just so dang tempting to just put a single hose with two clamps between those two nipples.... No need to find two big fat bolts or plugs of some kind and "4" hose clamps... Fine in an emergency road repair short term, but don't be lazy!

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Thanks Jim.......I've got a brand new valve, but the screws holding the old valve just won't come out. I don't really need heat, so if it's the same effect as shutting off the valve, I'm happy to keep 'em plugged.

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My take-away from the threads mentioned is that recycling hot water from the head back to the water inlet raises engine temperature. The stock system recycles water through the heater as stated and also through the manifold heater tube. This is supposed to be beneficial while the engine is warming up, before the thermostat opens . The manifold heater tube has a hot-closed thermostat.

I tried several things: leaking heater valve (coolant on floor), heater bypassed (looped), looped with restrictor, and currently everything plugged. Seems to run cooler now.

I tried the Dorman rubber caps but they were shot after 6 months. Now using tapered rubber plugs (about 35 cents each at Ace hardware) in the stock tee fitting on the side on the engine, with silicone caps (M-C) clamped over them for safety.

A BSPT plug is available (M-C) for the water outlet on the head. I've got one, but I hooked a short piece of semi-clear high pressure silicone hose (M-C) to it as an experiment; now I can see the coolant level without removing the radiator cap.

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See John Coffey's response to the thread Blue posted today for an overheating issue on cylinders 5 & 6. This was also discussed previously. Other than using the now-rare competition head, hooking the head outlet to the thermostat was discussed as a fix; there was a question about which way the water would flow unless it was introduced at a tee between the thermostat and the radiator. I bought the silicone hose to do an experiment to check that, however it's not clear enough to see which way the coolant is flowing. This only relates to racing anyway, I think, a non-issue otherwise.

I want to get my heater working again, if only to defog the windshield. Hope I can get the horribly corroded valve out.

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