Recently, after having my 2006 MC Sport Convertible detailed, the shop owner advised me not to run my car through car washes, saying the soap used in them is quite acidic and over time it will ruin the side window seals. What's your opinion about this?

 

I'd imagine he's correct. Generally car washes are bad for a lot of things, but most everything washes away. Acid does eat rims as well and I would be inclined to think soap and drive through washes are terrible for a canvas top.

 

The soap is the least of your worries. What about the abrasive brushes and the resulting swirls in the paint plus forced jets of water on a convertible?

Keep your convertible away from the car washes and DIY.

 

+ 1 for bbqhog's concerns. Thats why I always handwash when weather permits. During cold weather days (less than 45 F) I just rinse off the dirt on a regular basis with a pressure wahser. My local area self-wash car bays are really nice and carry the spotless rinse (which is basically distilled water) whci I use after I finish a round of high pressure rinse to minimize the risk of water spots. The brushless washes use high pressure jets (and some of them have hydroflouric acid in the wash soap mix) to compensate for the lack of a brush to get the dirt off. That can't be good for the finish of the paint in the long run. For one they never get all the dirt off and worse you have the kids waiting outside to wipe all the water off the paint (which still has mild dirt on it)with their dirty microfiber towels. This is clearly a recipe for paint swirls which show up more prominently in dark colored vehicles. If you really are one who keeps a car for a long time (5 or more years) and would like to keep your paint in mint condition (like me) then learn good handwash technique and DIY.

 

DO NOT RUN YOUR CABRIO THROUGH A BRUSH DRIVEN CAR WASH.
JUST THE WEIGHT OF THE BRUSHES CAN DAMAGE THE TOP. I go to a quarter wash and for $1.50 wash and rinse the bottom half of the car, including getting up in the wheel wells and power washing out the brake dust. You can't do that in any car wash. I do power wash with water only the back of the top . it tends to collect a lot of dirt. I hand wipe it all dry. The top will be slightly wet from the over spray and that's just enough to wipe it clean. I treated my top with a canvas top preservent too. The whole operation takes less than 30 minutes.

 

I was told the same thing. Now I either do it myself, go to a place that actually hand washes, no running through a track, or when I feel rich, have the guy come to my house.

 

Problems with the soap and the seals? That's a new one for me. There are lots of other reasons (mentioned above) not to use those auto washes.

Those drive-thru washes will install swirl marks quickly if anything touches your car. Just watch that mud-encrusted SUV go through in front of you and now you know what is being ground into your paint. Even the 'touchless' washes are tough as the detergents used are very strong (because of the touchless nature of the wash) and will strip any wax you have on the car very quickly.

 

Side window seals are the least of the problems.

Mark