Creaky car doors can be annoying. That horrible noise is also an indication that wear is taking place in the door hinge. Left unchecked, the hinge will soon become sloppy, resulting in a sagging, difficult to open and hard-to-shut door. Fortunately, if taken care of early, the cure takes only minutes and can save the do-it-yourself car owner hours of labour and aggravation.
Open the offending door completely.
Locate the door hinges and keep-open device. The keep-open may be a thin metal strap located in the door jamb approximately half way between the top and bottom hinges or it may be incorporated into one of the hinges.
Shake the penetrating oil vigorously and spray the pin area of both hinges. The pin is located at or near the centre of the hinge. Also spray the keep-open device liberally.
Open and close the door multiple times to work the penetrating oil into the hinge pins.
Penetrating oil is manufactured by several companies. Some common products are WD-40, PB Blaster and Liquid Wrench, to name a few; they are readily available at any store which sells auto parts. Lubricate the door hinges often to prevent rust from coming back.