I'm looking for DIY info on replacing the valve cover gaskets on my 03 GC. Also would like to know if there are any recommendations on what should be replaced while I have things apart for the valve job.

 

I am assuming you have basic knowledge of mechanics,safety issues, tool use etc. Also you have the 3.3 or3.8 engine.
Forward facing valve cover should be obvious and simple; remove cover, clean up valve cover and head surfaces, attach new gasket to cover, replace, and torque to specs.
Rear cover is a little more difficult; Remove the hood, remove winshield wiper arms. Remove plastic cowl, (snap in pins) then remove metal cowl, that holds the winshield wiper assembly, 4 or 5 bolts across the front, don't forget to unplug the winshield washer hose and electrical plug. Removing this cowl will expose enough of the rear facing valve cover to replace it fairly easy. Its also exposes the spark plugs if they are due to be changed. Whole job for a DIY person is 2-3 hrs. Tools required; 10mm. 13 mm 15 mm sockets, phillips orT25 torx head driver, also another set of hands to help remove the hood so you don't send it through the windshield.

 

You don't need to remove the hood. Just remove the wiper module to replace the rear valve cover gasket. You will need a 8mm or 5/16 socket to remove the valve covers. Also inspect the fuel injector harness too. They like to melt together.

 

Correct about the hood. Small amount of work to eliminate a possible bump on the head. Sorry, forgot about the 8mm. also.

 

No problem, But I don't use the hood prop to hold the hood open. I use a broom stick. That way i don't bump my head.