My daughter has a 99 Mazda 626 4 cylinder. It needs a new valve cover gasket. Is this is a difficult install? If not, then is there anything I need to be aware of?

Easy job, just don't gouge the machined surface on the top of the cylinder head. You may want to apply a small amount of Permatex sealant in the corners near the camshaft. Otherwise, oil may leak and deteriorate the timing belt.

Also, torque the cylinder head cover nuts to 84 lb.-in. starting in the center and working outwards.

Be extremely careful when you do it and keep any debris out of the area

Thanks for the replies.

Tex, you stated, "just don't gouge the machined surface on the top of the cylinder head"

Is the surface steel or aluminum?

I don't have a torque-wrench, but would 84 inch/pounds be what most of us would call "snug".

Aluminum.

Because of the rubber grommets, it can be difficult to gauge.

http://www.familyhandyman.com/DIY-Projects/Car---Truck/Car-Maintenance/how-to-fix-a-leaky-valve-cover-gasket