Water in E39

This may be an old question. Have a 97 E39. Runs great with 87K. Sits under an oak tree at times. When AC is running for awhile, there is water percolating in the center console air vent and gushes out of the rear console vent when going slightly uphill. Never had this problem til recently. May have sat in a rain storm

Mechanic tells me that Air filter drain under the hood had clogged and therfore water got into the system?. They corrected this problem but still drains after 3-4 days. It has not rained on the car now for over a week.

I think the AC condensation water is being introduced to this somehow. If it is rain water then it should purge itself. If anyone has the diagram of the drains on E39 I would appreciate it. I would like to see where potential cloggings on drains may be. Thanks

The drain hoses for the air conditioner are puluged.
Blow air back in the the 2 hoses on either side of the transmission. BMW could not fix the problem. Spiders can cause it to clog but blowing it back cleans it out enogh to work. Otherwise you will need to take apart and I have never done that.