Our heater core was leaking so hubby bypassed it. Now it's winter so we needed defrost so husband rigged a pump and put Bars stop leak thru core only. Then reconnected with different hoses. Then water was leaking out a metal tube or nipple in the firewall, and he could find no other hose that remained unconnected, so he simply blocked the nipple off, and there is no leakage and we have heat. THEN he found the old heater core hose and realized it was a "Y" hose and the smaller hose section should be connected to that nipple. I want it hooked up properly because I think it's a bad plan to remove a hose when you don't even know where it leads. He is angry with me because he says it's not important and can be left "as-is". Our daughter will be driving the car and I want it safe and don't want to overheat and blow the engine. Please help settle this and tell us whether it's okay blocked off or not and where does that hose/nipple lead and what is the purpose. It it just for climate control or ??

 

Thank you so much! We really didn't want to use a stop leak, but you know how hard r&r for a heater core is!! That's why we ran it thru the core only using a pump, then rinsed out before reconnecting to the system. I will use a citric acid flush as you recommended. I appreciate you taking the time to explain the function of the hose. We are going to reconnect it, based on your information. Yay! No more arguing! Now we can move on to my '72 300SEL.