I would change the valve cover gasket and the thermostat housing. I had a buddy do my valve cover gasket because I have never done one before. My gasket came off in about 7 pieces. The one we replaced it with was twice as thick. With the thermostat housing, it would be best to change now before it starts leaking. That only took me about 10 minutes to change. Also if you're ever curious about your valve cover, if there is oil on your spark plugs then it also means its gone bad.