Drain line between passenger side carpet and firewall

[ajgarvin]

I had a drain line clog in the roof well on the passenger side of my 1998 Boxster. The carpet and, more importantly, the foam rubber bonded to the underside of the carpeting got soaked. In order to dry it out and prevent mildew, I had to remove the entire floor carpet (this involved removing the seats and center console, among other things, and was a complete pain).

While I had the carpeting out, I noticed that there's what appears to be a drain tube coming from behind the dashboard on the passenger side, down along the firewall fairly close to the center console, and terminating into the floor. Weirdly, the tube seems to terminate into an interior layer of sheet metal and the lower level of sheet metal at this point is solid, so it doesn't extend to a penetration to the outside of the car. Before I reinstalled the carpet, I made sure that both ends of this plastic tube were securely seated and that the boot at the bottom end was properly seated in the hole in the sheet metal.

Does anyone know what this tube is for? If it's a drain tube, how is whatever is draining through it supposed to get to the outside of the car? To my dismay, I've discovered that the underside of the carpet in this area is wet again; not soaking wet like the first time, but definitely wet.

Edited October 10, 2011 by ajgarvin

[1schoir]

I had a drain line clog in the roof well on the passenger side of my 1998 Boxster. The carpet and, more importantly, the foam rubber bonded to the underside of the carpeting got soaked. In order to dry it out and prevent mildew, I had to remove the entire floor carpet (this involved removing the seats and center console, among other things, and was a complete pain).

While I had the carpeting out, I noticed that there's what appears to be a drain tube coming from behind the dashboard on the passenger side, down along the firewall fairly close to the center console, and terminating into the floor. Weirdly, the tube seems to terminate into an interior layer of sheet metal and the lower level of sheet metal at this point is solid, so it doesn't extend to a penetration to the outside of the car. Before I reinstalled the carpet, I made sure that both ends of this plastic tube were securely seated and that the boot at the bottom end was properly seated in the hole in the sheet metal.

Does anyone know what this tube is for? If it's a drain tube, how is whatever is draining through it supposed to get to the outside of the car? To my dismay, I've discovered that the underside of the carpet in this area is wet again; not soaking wet like the first time, but definitely wet.

AJ:

From your description and the location of the tube, it sounds like it's probably the drain tube for the water that normally drips from A/C operation.

It is supposed to end up outside (underneath) the body of the car. When it gets clogged (or is improperly routed), it will soak the foam under the carpeting.

Regards, Maurice.

[ajgarvin]

From your description and the location of the tube, it sounds like it's probably the drain tube for the water that normally drips from A/C operation.

It is supposed to end up outside (underneath) the body of the car. When it gets clogged (or is improperly routed), it will soak the foam under the carpeting.

Regards, Maurice.

Maurice,

Thanks for your reply. You are correct that the line I described is the AC condensate drain line. And I now believe it does exit through the floor of the car. In any case, it seems in good condition and firmly seated at both ends. The reasons I had thought it might be something other than the AC drain are as follows...

I reinstalled the thoroughly dry carpet in the thoroughly dry car. The car then sat, undriven, for over a week, waiting for me to have time to reinstall the center console and put the seats back in. When I was getting ready to reinstall the passenger seat, I slid my hand under the carpet forward of the passenger seat to extricate the wiring harness. That's the only reason I discovered that it was damp under there again. The dampness seems to be localized forward of the passenger seat, so I suspected the drain line I described. The AC was never used during the time while the car sat, but it did rain pretty hard.

This leaves me wondering:

1. Could a clogged drain line other than the AC condensate drain cause only the carpet forward of the passenger seat to get wet from underneath?
   
2. Could water from a hard rain end up in the AC cooling coil compartment, needing to drain through the condensate drain tube?
   

Interested in thoughts and theories as to what my leak problem is.

Edited October 11, 2011 by ajgarvin

[Loren]

Click to englarge...

[1schoir]

From your description and the location of the tube, it sounds like it's probably the drain tube for the water that normally drips from A/C operation.

It is supposed to end up outside (underneath) the body of the car. When it gets clogged (or is improperly routed), it will soak the foam under the carpeting.

Regards, Maurice.

Maurice,

Thanks for your reply. You are correct that the line I described is the AC condensate drain line. And I now believe it does exit through the floor of the car. In any case, it seems in good condition and firmly seated at both ends. The reasons I had thought it might be something other than the AC drain are as follows...

I reinstalled the thoroughly dry carpet in the thoroughly dry car. The car then sat, undriven, for over a week, waiting for me to have time to reinstall the center console and put the seats back in. When I was getting ready to reinstall the passenger seat, I slid my hand under the carpet forward of the passenger seat to extricate the wiring harness. That's the only reason I discovered that it was damp under there again. The dampness seems to be localized forward of the passenger seat, so I suspected the drain line I described. The AC was never used during the time while the car sat, but it did rain pretty hard.

This leaves me wondering:

1. Could a clogged drain line other than the AC condensate drain cause only the carpet forward of the passenger seat to get wet from underneath?
   
2. Could water from a hard rain end up in the AC cooling coil compartment, needing to drain through the condensate drain tube?
   

Interested in thoughts and theories as to what my leak problem is.

AJ:

Although it's not very clear from the factory manual diagram, there are two drain holes for water that may come in at the front of the base of the windshield.

The drain holes are located on either side of the battery tray, closer to the rear firewall. If those get clogged (or if the rubber flange on either one of them gets dislodged or distorted), water from rain or from washing the car could end up in the passenger compartment, under the carpet where a passenger's feet would be.

There is an explanation and a photograph or two on Mike Focke's Boxster Pages, here: http://sites.google....2/drainsdiagram

Regards, Maurice.