if you have heat and and it is working OK. and if you squeeze the lower radiator return hose and feel water flowing. most likely it is the electronic fan not coming on.
Perhaps plugged radiator - have it boiled out or replaced
Could be your electric fan on the radiator is shot, or the relay is bad.
Thermostat and radiator
Cracked.head
Try replacing the radiator fuse relay
This is likely a stuck thermostat.
The top radiator hose is above the thermostat. If the top radiator hose is hot, the thermostat is opening. The thermostat is not the problem. Perhaps the radiator is clogged up or the water pump is bad. Look elsewhere.
Air in the system. Bleed the system. Defective thermostat, clogged radiator, defective cooling fan or fan clutch.
broken thermostat; blocked hose to radiator or hole in hose; leak in radiator; etc..
That depends on the thermostat. If it's a 185 thermostat, the engine should run at 185. If it's running too hot, check the thermostat, radiator and water pump. If it's running too cold, replace the thermostat.
Is you Geo Tracker overheating or the temperature is running almost hot then you need to change you thermostat
Follow your top radiator hose,your thermostat is in cover,its bad,pull out and check by putting in hot water at 180 degrees,it should open,then close after you take out of hot water,is it staying open,it needs to be replaced.