I am surprised with a 160 therm that it would get that hot,
my 235 never came close to running hot, well it did once,
we were in a very long fourth of July parade with very slow movement and at the end of the parade it was getting hotter then normal and then cooled down as we got on the hi-way........now my 52 car with the 350 and air is another thing, in stop and go traffic it can go to about 215/220 in a hurry, I just click on the electric fan to keep it from getting hotter.........
probably nothing for you to worry about unless it has just started doing this..that still seems really hot for 90 degree weather, I think of hot weather being above 104...