When driving in traffic, highway, etc my 89 sho heats up to 3/4 range. The fan comes on then goes down a bit. I changed my thermostat(original ford), temp sending unit, fluids, still the same. Will 180 thermostat do the trick. I heard that 89-95 sho need 190 to operate properly. Could installing a 180 thermostat harm my engine? Any feedback.thanks