[bjs2oo7]

Looks as if I have been filling expansion tank with oil, but runs the same as always only reason I thought to check the coolant is because the temp gauge seemed to be sitting a tiny bit higher than normal, should I pressurize the coolant system to check and how? Should I a compression test and how? (can I rent a diesel compression tester?) Also what else should I replace and or adjust at the same time I do the head gasket besides the timing belt, I am planning on driving cross country with the car and want to be confident,
any help is much appreciated