AC Return Air ?

88911coupe · 06-01-2003, 04:11 PM

Ok, Just spent several hours cleaning out my evaporator coil and sealing up the triangular return "vent" in the pass. footwell. My concern is that there does not seem to be a lot of air going back to the evap coil through this port with the ac on high, although I sealed up the opening from the footwell into the evap box very well. I can feel another port just inside but shouldn't a good amount of air be going back through this port? Also, where does this second return port lead to...somewhere in the driver footwell? I did not see anything there that looked like a vent. BTW, it seems to be working a bit better but not really as much as I'd hoped. Getting it cleaned out still needed to be done.
TIA,

Joeaksa · 06-01-2003, 04:56 PM

Buck,

I can take some pictures if you like of the evap unit. I have an "extra" one that is out of a car. Do you know that there are two intake ports on the bottom of the evap unit? I did not...

One draws air from the pax footwell. The other goes into the tranny tunnel area and draws air from this area. Never knew that there were two intakes for the evap unit and this may be blocked or need cleaning.

Joe

88911coupe · 06-02-2003, 04:15 AM

The second one is the one that has me baffled. I can seem to figure out where it opens into the car. Are you saying it's down on the tranny tunnel? If that's the case mine may be blocked.
Thanks,

Joeaksa · 06-02-2003, 04:59 AM

Buck,

I remember in my older car that the shifter access cover was a grill. Air could get through the top. I also wonder if there are other vent holes in the shift linkage tunnel.

There is a second "intake" in the evap unit and it evidently will pull air out of the shifter tunnel if there is a way to do so. Why I havent the slightest but it really surprised me.

Joe

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by Joeaksa
Buck,

There is a second "intake" in the evap unit and it evidently will pull air out of the shifter tunnel if there is a way to do so. Why I havent the slightest but it really surprised me.

Joe

Eventually the air in the interior of the car will have cool so pulling the air from the interior will require less cooling compare with pulling hot outside air.

Some cars (not my Porsche) has a recirculation system so that only the air inside the car will circulate thru the evaporator in the summer and heater in the winter.

jdowty3 · jdowty3's Garage

Hey Buck. I was at Jack's on Saturday and we spoke a few time about AC and the evaporator. I have mine out right now for a major upgrade project. Mine is an 83 so I know there are some difference between the 2 systems. Does the 88 have the footwell blowers? I think the 2nd hole in the bottom of the evaporator draws air from the drivers side behind the pedals as well as some fresh air through the shift tunnel. The tunnel access panel should have a fiber gasket and not much air will be getting past it from the cabin. I believe the air draw from the tunnel is designed to be minimal so that your recirculating the inside air. The most important thing is that the seal around the evaporator (to the sides of the box) is good so that the fan pulls air through it, not around it. The seal on the top on the box (where the fan mounts) also need to be tight so the fan doesn't pull air from outside the box. If you want to see it out of my car, email me.

88911coupe · 06-02-2003, 08:33 AM

Thanks for all the replies. I think I know where the "second" vent/port get the air now. There's several holes drilled in the side of the center tunnel, just to the right of where the foot rests when on the gas pedal. Also, there's an opening on the shift tunnel just ahead of the shifter but it does not seem like much air could get through this. I checked again last night and there is definitely air going back through the footwell opening. I made sure it is sealed from the footwell to the evap box so it's not pulling hot outside air in.
Later

derkpitt · derkpitt's Garage

Is this it?

A/C work, Evap box