Every now and then I do the same thing. But I do a proper strip down of the cooler as well
Taking it off to get to the gpu chip, over time the thermal paste tends to dry out.
So I suggest you have a go at that to lower the temps.
Clean all of the old paste off the Gpu die, then apply a blob of thermal paste in the middle of the Gpu die. Use some sort of plastic card and spread it in a thin layer all the way over the gpu die and then put the cooling unit on to the card. It normally will lower the temps by a few degrees. if the card was hitting 90c or more under heavy load then i would be concerned.