Quote Originally Posted by T16 View Post
These are the boot air vents, and if they are the same as every other MG Rover afterthought, they are sealed to the body with a "foam" gasket, and held in place by rivets.....

Normally these are ok, as they are not usually directly in the water line, being hidden by the bumper. However if for some reason your bumper might have been chinese, or not quite fittted 100%, I guess its more than likely it would let in water where it meets the quarter panel.
Well, none of mine are. There is a proper rounded profile shaped rubber gasket held in a groove moulded into the inner face. Fixing is solely by 4 plastic clips which are part of the plastic moulding. Often people yank them out from the boot-side without releasing the four clips ('cos its a bumper off job) and then glue them back or fix them with foam rubber and pop-rivets or some-such. Thereafter they leak forever. I'm pretty sure they are the same on all 75's / ZT's?

Water gets to them by running down the outer wing panel to the join with the rear bumper "arms". That join is no way water-tight, and is not intended to be. In fact the shape of the lower wing body-panel and that of the bumper inner surface almost directs the water then onto the vents. If you use a hose on the upper part of the wing you can see exactly how and where it gets through!

David