2004 Buick Rendezvous Owner's Manual - Page 131

Roof Rack System {CAUTION: If you try to carry something on top of your vehicle that is longer or wider than the luggage carrier - like paneling, plywood, a mattress and so forth - the wind can catch it as you drive along. This can cause you to lose control. What you are carrying could be violently torn off, and this could cause you or other drivers to have a collision, and of course damage your vehicle. You may be able to carry something like this inside. But, never carry something longer or wider than the luggage carrier on top of your vehicle. If you have the luggage carrier, you can load things on top of your vehicle. If you do load things on the top of your vehicle, you must load them on the luggage carrier crossrails. Notice: Damage may be caused to the roof of your vehicle if anything is placed directly on the roof. 2-41