Engine running hot

164°F would be very cold actually. That engine should be running at around 210°F. First thing to check would be the level of the coolant. If it is low it can result in the temperature sender not reading the actual temperature of the coolant/engine.
If the coolant is full then the next thing would be to use a non contact thermometer or a mechanical probe gauge to verify that the coolant is really at the 164°F. It would not be the first bad sending unit or bad gauge I have seen.
If the coolant really is at that temperature it could be that the thermostat has failed and stuck open or the cooling fans may be operating incorrectly and over cooling the engine. For that listen for the fans running when they should not be, IE; the engine was started within the past five minutes and was cold and no AC or defrost. If they are not running then it is likely a bad thermostat. Try to use OEM if it has failed, most of the common after market units have gone way down in quality over the past couple years.