[rolling money pits]

the only way to get "cool" outside air into the car is through the vent in the passenger side kick panel. it's basically a plenum with a flapper, actuated by a vacuum diaphragm, that seals against the cowl right behind the blower motor.

the valve/flap defaults to the closed, or "recirculate" position, with no vacuum applied. with vacuum applied the flapper closes against the cabin and allows for outside air to be drawn from the cowl, then blown through the evap box and into the cabin through the vents.

if the whole system is working properly and you have the control unit set to A/C and the temp lever to full cold, that will be the only way you get get "cool" outside air to blow from the vents. if that diaphragm is ruptured, otherwise inoperative, you'll essentially be running recirculated air all the time.

if the ambient air temps are say 80*, the air blowing through the vents will be at least that, so keep that in mind. also keep in mind the blower/heater core box isnt the highest tech when it comes to sealing, so depending on the condition of the internal seals and rubber flaps, you're always going to get some cross over heat coming through, it'll just depend on how much.

check to make sure that passenger side diaphragm is A - getting a vacuum signal when it's supposed to and, B - is actually working properly, closing up against the cabin.

[2002Z4CSS]

Sounds like the temp blend air door is staying open to the heater core. When you move the cool and warm knob, listen for the door to close.

[gtoformula]

I got tired of hot air bleeding through the heater core during the warm months (most all of them here in Texas). I have a non AC car and it didn't have a water control valve to the heater core so hot coolant would flow through the core at all times. There is always some air bleed through the system so hot air would always come through. Stopping the coolant flow through the heater core stops the heat from coming through the heater box. I installed a vacuum water control valve a few inches ahead of the heater core nipple and used an extra vacuum fitting on the rear base of the carb to the control valve. I need to plug the vacuum fitting if I have the valve disconnected, but that is only twice a year (once when it gets warm and once when it cools down). You can also buy a mechanical control valve, but the vacuum system seemed easier as the car does not have a factory water control valve cable. Just a thought.