GM Service Manual Online
For 1990-2009 cars only

The mast antenna can withstand most car washes without being damaged. If the mast should ever become slightly bent, straighten it out by hand. If the mast is badly bent, replace it.

Check occasionally to make sure the mast is still tightened to the roof. If tightening is required, tighten by hand.

If you are putting a protective cover over the vehicle, remove the mast by hand.