skipmyles

is there a water cut off on the heater box 2001 rx 300 would like to shut it off in the summer would have to help some
thanks

Derrick71

There's not going to be a valve or anything like in a home plumbing system. You'd have to disconnect the lines that pass through the firewall and splice them together. Also plug the lines through the firewall to keep anything from getting into the heater core.

I'm very curious. Why would you want to do something like this?

salimshah

Search on MIX Servo. This servo controls hot/cold based on your thermostat (Cabin temperature setting)

Salim

fastnoypi

what are you trying to accomplish to help in the summer? Attempting engine cooling or additional cabin cooling?

skipmyles

just getting rid of heat dont have to use ac but heat coming off of pipes keeps cabin hotter

fastnoypi

as salim pointed out, you want to ensure your air/mix servo is working properly. Any slack in the mechanism will allow the flapper door blend in heat.

salimshah

As scientist you are right, but the heat exchange (to cabin) is shut off. I would suggest fix the thing that is broken.

Salim

skipmyles

the pipes coming into cabin are hot am
nd not behind flapper door

salimshah

Heat exchanger has different chambers and the air is diverted/blocked to get you the air inside the cabin as desired hot/cold. If you are getting undesired air in cabin then examine the duct and servos that are responsible for the air flow.

The coolant has its own circuit (loop). If you want to override the plumbing then make sure you provide a bypass and not just a block the inlet. When you make the bypass, you might compromise the state of the heat exchanger. Stagnant coolant or worse still air will bring corrosion.

It is your vehicle so you know the best for you. I tend to trust the engineering put in by the manufacturer. (other than overworked mode servo ]

Salim