In BIOS if in anything, but really running components on 85C is not healthy for them so instead of removing the limit, you should think how to lower the temperature. Usually some laptops start to overheat due to age as vents gathers more and more dust and components starts to not be cooled properly, you could also check if you vents has open space to gather air. Either way best would be to do what Paul saying, contact ASUS, the might help you out 