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90 Corolla 1.6 capping/shunt heater core

the upper hose going to the firewall connects to a plastic gate valve with a wire cable controled by the temp slider lever on the dash.It’s starting a slow leak and I don’t need a heater so I want to cap it off. Should I cap the other end of this hose at the water distributor(for lack of the name) ? Also I have often wondered if there is a chemical which could be rubbed on the male metal stubs? to prevent rust BUT not be slippery for the radiator hose to clamp on. Maybe a rust coverter primer. Both my toyotas are 20 yrs old…thanks, Mike

I don’t really like the idea of capping off the heater core but here’s how to do it. Just loop a piece of hose and clamp it to the heater core inlet and outlet. The remaining hoses from the engine need to be connected together with a plastic or metal coupler so that coolant can flow properly. You can pick up a straight coupler at most auto parts stores. The best course of action though is to repair the leak and leave the heater core operating as it should.

Are you seriously that cheap that you won’t just get a heater control valve?
FOUR SEASONS Part # 74637 $35 at www.rockauto.com probably $10 at salvage yard.
And the stubs will be brass no they won’t “rust”.