MoMata

So I've had my 370z for a bout 1year now and it has 70k miles...my issue is that since I've had my car it's been to the dealership about 10 times because my clutch has issue on losing pressure.. I've already replaced the clutch petal assembley, master cylinder,slave cylinder,clutch line,throw out bearing,new clutch kit... The Nissan dealership sais that the fluid keep getting burned and they still can't figure it out... What is the problem?? What could it be??