Ok so I'm gonna write this up as descriptive as I can. I have a 2000 X with 118xxx had it for 2 months now last weekend after a long drive on the highway and getting off of the highway and slowing down vehicle over heats Added some oil because I was pretty lo and topped off coolant. Got in drove another hour no issue. After it cooled I drove home about an hour and a half. It was all mixed driving. So.. A week goes by without any issues haven't done extended driving but has gotten up to temp. No over heating. So a week later I replace valve cover gasket to stop oil leak. All is well do oil change at same time top off coolant barely took anything. Drive 30 min highway and feels great. get to where I was heading and it's steaming but temp is fine. Overflow tank is to the cap. I pull some coolant out with a turkey baster and let it cool. Vehicle cools and I'm heading to another destination get about 15 min into trip all highway. Get off highway and starts overheating again. Pull over pop Radiator cap and top off coolant. Took what I had taken out earlier. Get in start it up and temp goes to normal I go to autozone and replace radiator cap. Drive 40 min not a problem. Then drive an hour home without an issue. Drive it around locally and never an issue. So... I'm looking for advice. Thinking head gasket and am fully prepared to deal with it and would like someone to point me in the direction of a d.i.y or offer any advice. Thanks. I'm pretty good at working on vehicles just never got into tearing apart the whole upper engine. I have an fsm. Any ideas?