Max A/C = closed heater core valve

[Cheetah-kins]

This is an interesting thread. I have first year Miata and the AC works well, but iI remember reading a thread a while back in another forum about a guy installing a valve in one of the hoses to the heater core that could manually stop coolant to the core. The author mentioned that he would close it at the start of spring and open it sometime in the fall, this allowed the heater core to be bypassed so you avoided a source of heat in the dash when using the AC. He said the AC worked much better after doing this modification. It sounds very much like what some posters in this thread are saying their vehicle does automatically when running the AC on max. I'm planning on having my AC shop eventually put a valve like that in my system, even more so after reading this thread. Can't be too cold as far as I'm concerned.

 

[eljefino]

I'd be concerned about putting in a stop valve without some sort of bypass to get the coolant back to the engine. If the thermostat is closed, all the water that could be sent to the radiator has to go through the heater core instead, unless the engine has an internal short circuit somehow.

 

[Cheetah-kins]

I'd be concerned about putting in a stop valve without some sort of bypass to get the coolant back to the engine. If the thermostat is closed, all the water that could be sent to the radiator has to go through the heater core instead, unless the engine has an internal short circuit somehow.

Yeah I can't remember the exact way it was done, but the OP said that it worked very well and did not stress anything out. I'm gonna be researching more before I get it done of course.

By the way, one idea I had a while back was to insulate the AC lines in the car. Ever notice under your hood the engine bay can be very hot after the car warms up, but the ice cold AC lines aren't even insulated? I find that odd because they are insulated in homes and businesses I've seen. I posed that question on an AC forum and several people said they didn't think it was a good idea or car manufacturers would be doing it at the factory. So I never insulated mine, didn't want to risk damaging the AC system. Still makes me wonder though, lol.