Even the least knowledgeable car owners know the basics of of required maintenance...oil changes, tire pressure, etc., yet many of the more experienced DIY'ers either don't know the importance of, or just put off cleaning drains. In either case, EVERYONE should be educated and practice cleaning drains on (at least) an annual basis. Personally, I place a lot of the fault on the car manufactures for not placing enough emphasis on proper cleaning and also for not placing a diagram of locations, preferably on page 1 (in big bold print) of the manual. Additionally, why can't the drain holes and tubes be of a slightly larger diameter...maybe a1/2 inch?
Now that the preachy lecture has concluded, I'll share how I don't even follow my own advice. First, I should state that my Boxster is never parked outside (therefore I reasoned that the drains don't need cleaned...yeah, I know), but in the past several years I've had three vehicles that have had issues linked to clogged drains. First was a '04 BMW X3...I was having some electrical issues (dead battery, etc) that led me to check on the battery. For those who don't know, the X3 battery is in the back below the floor in a recessed cubby. When I checked the battery, it was almost completely submerged in water caused by a clogged drain in the sunroof that led to water draining down the rear pillar and filling the battery compartment. I cleaned what I could, but ended up paying BMW to remove lots of interior trim (including the entire headliner)...and bought a new BMW battery. Lesson learned, right? Nope.
Next was a '01 Audi A6 2.7T...one day my wife was driving and I was in the passenger seat and noticed that the floor was slightly damp, not soaked, just damp. I had her drive though a car wash (while I was upside down in the passenger floor well with a flashlight) so I could look for water intrusion. I found a few drips from the passenger floor heat vent, so at home in the garage I started to investigate. As I discovered on this model the climate fresh air intake was mounted next to and just below the shroud at the bottom of the windshield (where the wipers reside) and upon pulling the cover and filter, found water in the intake down to the blower motor an onwards to the foot well vent. I pulled the passenger seat so I could pull up the carpet and to my surprise, I found the entire front and rear footwell filled with several inches of water, completely submerging various electronics, and the carpet only felt damp because in many locations the carpet didn't set on the floor pan, but rather on raised cross supports. I shop-vac'ed at least 8 gallons, and propped up the carpet and let dry for a week. As it turned out, the cause was the drain at the base window shroud, and not from obvious debris (leaves, etc) but from a blockage in the drain tube itself.
Next (yes, I still didn't learn) was a '10 Audi Q3...passenger floor felt damp (sound familiar?). I pulled up some of the carpet, luckily only the carpet was damp. As I had experience with the other Audi, I started at the HVAC...nope, so car was off to Audi service, and to make the story short, after several attempts, they couldn't find the problem, and suggested it might be the door seal. I didn't accept this answer, so I started investigating at home. I started at the sunroof, and with it opened, I poured water in the sunroof surround (where the tracks reside) and found it really wasn't draining; I eventually discovered that when the sunroof "pan" overflowed, it ran down the interior of the A-pillar. Again, no obvious debris, just a blockage in the drain tube.
The reason I felt compelled to post this rant is due to the number of threads that read something like "my bla-bla-bla doesn't work" and usually the same couple of very helpful individuals respond "check your immobilizer"...which I am actually quite surprised that they aren't tired of posting the same response again and again. Is the location and design of the immobilizer a bad design? Maybe. Could some of the issues be solved by cleaning drains? Probably. Will whistle-clean drains solve all water issues? No, but at least it's something that CAN be done proactively.
I hope my little tirade motivates at least one person to clean their drains. If nothing else, it has prompted me to go clean mine tomorrow. Or maybe next week. Or at least before summer driving season....well, I'll get to it sometime.
