Sunroof rumble '98 Passat wagon

Rumble (pulsation in the cabin) from the sunroof, or a certain window being opened is caused my too much pressure inside the vehicle. If I open only my rear windows it causes my hatch to pulse, trying to open itself, but getting caught by the steel latch. When my sunroof is open, I get air being drawn up thru the floor vents, and the dash vents, no air really comes down from the roof (which is why you don't get wet when its open, while driving, when its raining a little). When the the sunroof causes this rumble you should be able to feel it as a pressure on your eardrums. Unless it's just wind noise, but from your description I don't think it is. The air deflector may help, can't say for sure as I don't have one, my sunroof is a non issue, tho it gets a little loud on the highway.

....If it is an air pressure problem, at least you know your vehicle is so damn air tight nothing can leak out, which is praise for assembly quality.

I have a 1999 German built Golf TDI, it is quite air tight. But my Mexican built 1991 Golf has so many leaks that opening windows does nothing to the accoustics, aside from making it slightly louder in certain conditions. In the winter I can feel cold drafts coming though the front doors, and hear them whistling to an exit somewhere at the back.... I think I would rather your problem then the air leakage problems of an older car ;-).

The owner's manual mentions this. In my Passat, opening the rear windows an inch or two relieves the buffeting.

-- Jeff '02 Passat 4Motion Wagon

Normal operation of course (and if you get it just right, it about makes one's ears bleed). Cheapest cure is to leave the sunroof glass sticking out about 4". The newest VWs do this automatically. To bypass it, you have to turn and hold the dial past a certain position.

And yes, those plastic defectors do help.