Hi guys, new to the forum.

I just bought a 2011 370z and was checking the fluid levels. Two questions: 1) How do you get off the cap for the reservoir? It doesn't have threads. Eventually I popped it off (applying pressure); however, there has to be an alignment trick to opening it. Turning it a certain way or something. 2) What is the optimal level for the fluid when checking cold? Should it be at the max or between the min and max? I say optimal because I need to bring it in for 15000 km maintanence and now the level is halfway between max and min. Should I top it off to max? Thanks