Condensaton inside rear window
 

After driving in rain and letting the car sit, engine off, I am getting a small amount of window (hardtop glass) condensation at the bottom of the window. I am guessing from the engine compartment that is bypassing the cover and upholstery. Anyone else have the problem? If you identified and fixed, How?

Never had any real problem with condensation, fogging, inside my Boxster that couldn't be explained by the weather conditions and which couldn't be quickly addressed by turning on the A/C. My car had just the soft top with the plastic rear window but in defrost mode the system would clear any fogging in practically no time.

It is important the engine cover be properly installed and secured. That every one of the screw locks be tight. I had this cover off very seldom but it always went back on without a hitch and always sealed the engine compartment.

If the engine compartment cover is secure my WAG is there is a water leak, water is getting into the cabin. This can be from the hardtop failing to seal properly. Be sure the rear body water drains are not blocked. To get to these will probably require the top be removed. (For access with the soft top the procedure was to put the top in the service position which had the clam shell wide open. The rear body water drains are located on either side of the rear of the soft top under the area covered by the clam shell arms.)

Might as well check the front body water drains too. These are located under the plastic panels on either side of the battery box.

Check along the door bottoms for any signs of dampness. With these cars getting up in age the door membranes will start to go bad and when they do they let water from the wet side of the door into the dry side and this can have water seeping out the door into the cabin. Even if the water remains in the door this build up of water can cause door/window electrical "gremlins" to appear and if ignored can then have electrical gremlins showing up at other areas of the car.

you probably have a leak somewhere, maybe down in the rear well where the top is stored and the drain is clogged. Maybe capture a dehumidifier inside the car to dry it out before anything gets damaged

I have a guess that the engine cover is not quite sealing. I know that the center fastener in the front is not fastening. Have been trying to find a replacement fastener but the only one I can find is in the UK and they want over $25 for shipping. Will keep trying.

try contacting woody aka itsnotanova via a private message on the 986forum.com. He parts out wrecked Boxsters. Honest and helpful.

Woody is sending me two. Great to have someone that has access to parts so easily reached. Thanks for your lead and info.

Woody had the part and shipped to me quick. Thanks