HVAC Extra Heat?

[Roger S.]

When the car is sitting in the driveway I can get the air temp down to 53F w/ the AC on max. Once driving the temp goes up to about 68F w/ the AC still on. When I turn off the AC the airbox at the passenger's heat gets warm. I have the heater hoses valved off and the air doors operate properly in the driveway. I have found the condensate drain under the evaporator not to have the rubber hose on it so I have a 1" opening for hot engine compartment air to enter the HVAC air box. This opening is about 12" from the exhaust manifold/exhaust pipe. This will be correct tomorrow. I have cover the airbox side facing the exhaust manifold with aluminum faced insulation. I find it hard to believe that this 1" opening will allow enough hot air into the air box to affect the air temp 15F. Are there other places in the interface with the engine compartment / airbox / firewall that have been found to leak air into the airbox or the plenum? How the heater core inlet tubes sealed from the airbox?
Roger

[Harmon C.]

Re: HVAC Extra Heat?

Is the vent seal behind the passenger side kick leaking hot air?

[Dick W.]

Re: HVAC Extra Heat?

You are definitely getting outside air in the car. Another thing to check is that all your doors are operating correctly. I have found several cars that the blend door would lack 1/2" or more closing. All the doors have adjustments. If you have a Mity-Vac you can check each individual door after removing the RH dash panel. Unplug each door and check for operation using the Mity Vac as a vacuum source.

[Roger S.]

Re: HVAC Extra Heat?

What is the vent seal?

The air door behind the kick panel opens when the recirculation air, max AC, is called for. When normal AC is called for the air door shuts. The air door in the plenum shuts also when the recirc air is called for. Normally this door is open to the plenum. This door opened to the plenum allows outside air into the HVAC system and when it is closed then interior air is recirculated through the system if the airdoor behind the kick panel is opened. I have replaced the weatherstripped on the bottom of the hood to prevent engine compartment from going into the plenum.

I have readjusted the blend door located in the airbox after the evaporator and before the heater core and its bypass. With the AC on this door had about a 1/2" gap to the sealing surface. With no water going to the heater core the position of this door does not matter.

Roger