For 1990-2009 cars

Clean the weatherstrips and contact surfaces with cleaning solvent. Apply powder or chalk in an unbroken line around the perimeter of the trunk lid, door, door glass or hood. Surrounding areas must be free of chalk or powder. Close panel completely. Do not slam closed. The line applied on the weatherstrip will be marred where contact is good. A corresponding imprint will be on the mating surfaces. Gaps or irregularities in the powder or chalk line indicate a poor seal.