Installing heater shut off valve

[mjdriver]

So I'm wanting to install a shut off valve in one of the heater hoses to try an keep temps down in the cab for summer. I was just wondering which hose would be best, or is it a bad idea all together?

73 J series, 360

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[Stuka]

Personally, I like the heater in case engine temps get high, as then it acts as a secondary radiator, even if it will make the cabin super warm

I am not sure if the water pump will like having that coolant intake shutoff, or if the intake will like not having that coolant leave from the heater port. Both the radiator and heater feed into the same side of the impeller. Normally when a heater bypass is done, you feed the heater core input straight into the water pump so that the coolant still flows like normal.

So I guess, I am not sure sure if it will work or not. But I never bothered doing it, and I drove without AC here in 100+ temps.

[RamJetFSJ]

Instead of just putting in a shut off valve, I would use a bypass valve instead, so it can still flow when bypassed.

https://www.ebay.com/itm/Heater-Valve-5 ... 890.l49292

[sirrus]

X2 on using bypass instead of shutoff

[mjdriver]

Personally, I like the heater in case engine temps get high, as then it acts as a secondary radiator, even if it will make the cabin super warm

I am not sure if the water pump will like having that coolant intake shutoff, or if the intake will like not having that coolant leave from the heater port. Both the radiator and heater feed into the same side of the impeller. Normally when a heater bypass is done, you feed the heater core input straight into the water pump so that the coolant still flows like normal.

So I guess, I am not sure sure if it will work or not. But I never bothered doing it, and I drove without AC here in 100+ temps.

Hmm ya you have a point, Ill have to look into the bypass valve that others have mentioned. I live In florida and I don't think my heater cut off door seals very well, so I get some heat out the vent even with it off. About the over heating, I have an eBay aluminum 3 core radiator, stant 180 superstat, 7 blade flex fan, and toyota red coolant, on 95 plus days hauling my Honda rancher in the bed I don't see above 185. But it is nice to have the heater as an emergency.

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[mjdriver]

Instead of just putting in a shut off valve, I would use a bypass valve instead, so it can still flow when bypassed.

https://www.ebay.com/itm/Heater-Valve-5 ... 890.l49292

I'll look into this, thanks.

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[sansabarJ]

I concur with NOT putting in the shutoff . My 72 360 has a faucet type valve at rear of intake which I replaced with an exact replacement , a GM medium duty truck valve . I thought ,yeah just close the coolant flow to heater core .However it's now always open for flow .
I did use it once and noted my temp wanted to creep up on highway . Well ..whos doesnt right ? But , closed it off and it's fine . I agree you need the circulation flow from intake to water pump to promote proper cooling . I would bypass heater and loop hose as has been posted .Honestly , these trucks hardly require a heater at all if you in any moderate climate . Even with all the sound deadening Kilmat, carpet and so on , it needs the vents open most of the time . Cabs are pretty small .

SansabarJ