I recently bought my 16 year old daughter a 2007 X3 w/approx. 117,000 miles on it. It seems to be a pretty good car except for interior water leaks. About the second time I filled the washer reservoir within a week, I read where the rear window line runs under the console and can separate, leaking washer fluid into the carpet after I found the rear floors soaking wet. Promptly unplugged the line from the pump, plugged the pump and removed the wire plug - will fix it later. Thought all was well until the first rain a few days later. Found more water on the rear floors. I've been wet-vacuuming them for the last few weeks until today. You will be surprised how much water one can vacuum from the floor mat anchor holes! Today I started at the sunroof drains verifying they drained. I blew low pressure compressed air from the bottom up. The rears I wound up cutting them open behind the corner cargo covers then blowing air both ways before splicing them back with fuel line that had the same ID as the OD of the drain tubes. Then poured water from a bottle slowly from the top corners of the sunroof to verify drainage. Next I removed all 4 door panels. The rear vapor barriers had been "molested" (torn) and all 4 had some non-sticking spots. I used 2" wide HVAC foil tape to carefully seal all the edges of the vapor barriers all the way around. Then sprayed a garden hose at each window one at a time, opening the door and checking for leaks. The fronts did fine the first go round. The rears were more challenging. The biggest leak was from the nut of the bottom of the window regulator! I took both nuts off and sealed them with black RTV silicone, tightened them back, then put a bead around them again after taping. There were also some tiny leaks from around the foil tape joints which required more taping. I eventually got them both sealed. I used this method to successfully repair and seal the more severely torn vapor barriers on my 02 X5. I find it hard to believe premium segment vehicles such as my X3 & X5 would have these kinds of issues and hack mechanics don't help matters either! I'll have a week to dry the carpet out before next weekend's forecasted rain.

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Current Rides:
'88 635 CSI (mine)
'02 X5 3.0 ("tank thing")
'01 325CI Convertible (wife's)
'06 325i Sedan (daughter's)
'07 X3 3.0 SAV (other daughter's)
Guess who gets to work on them!