I was wondering if anyone else has this problem...
When the car wash brushes go over the top of my 2005 Bonneville, there is a load bang as the roof apparently pops down and back up after the brushes pass. Scared the heck out of me the first time. And I not too thrilled each time it happens.

Haven't had it with the brushes, but the blowers do in one of the car washes that I go to. Does it on both 2000 SSEis.

Now that you mention it, the blowers can do it too.
Both my Bonneville and Impala have sun roofs and the Impala never did that in over 100,000 miles.
It'* amazing that something like that was going on for 6 model years and Pontiac did nothing.

I NEVER use those car washes. First, they never do a good enough job.. Second, they can damage things very easily. Especially our cars since the side mirrors don't fold. I've actually been to car washes that specifically say NO Pontiac Bonneville, GP, Grand Am, etc. When I had my Maxima I used car washes occasionally and its roof poped very easily. The hood too sometimes.

It'* the sunroof.
Don't use the brush car washes. Your clearcoat will thank you if you don't.

I say NO to drive thru car washes, and plus. its way to much fun doing it yourself, its the best excuse to wake up on a weekend morning and spend hours of washing and detailing without anybody bothering you...

definitely don't use those brush types. talk about ruining a car'* finish. there are TONS of small pieces of junk on those brushes/mops. its like dropping your rag on the ground and then rubbing all that junk back into the paint. if you have to, only do touchless, but otherwise do it by hand. i would definitely recommend claybarring and waxing if you've done those auto carwashes a number of times.

otherwise about the roof, even mine does that, scared the crap out of me too, but that was the blowers.

I usually use the self serv power wash, but when its 16F outside... it'* the drive thru.
(Last night it got below zero)
Hand washing is the only way to get those freaking wheels clean of brake dust.

Drive-thru'*......= ...EVIL. Never use them. The guy before you coulda been driving a 1983 toyota corolla rust bucket and the brushes and scrubs would contain chunks of steel, you put your car in after that.....well you might as well wash it with steel wool. Im speaking from expierence....my first cara 1972 nova i took it through and i ended up with with gouges in the paint.....i bitched and complained and the owner got in re-painted but i had to chip in cause he said it was my fault as well for using it. Its your car.....your choice........I like mine shiny.....I wash it by hand. Besides, it gives youa excuse to get away from the wife.......haha jj love you babe if your reading.

Yeah washing by hand is the best. In winter I tend to run out to the touch less because its too cold and the water would freeze right on if I did it myself. The touch less washes don't always get your car perfect and sometimes there is still a little dirt left, but at least it gets all the salt and garbage off.