To address cooling system issues, first check the coolant level, drivebelt, tensioner condition, and temperature gauge operation. If the engine takes too long to warm up, indicating a stuck-open thermostat, replace it with a new one. In cases of engine overheating, assess the lower radiator hose temperature; if the hose isn't hot while the engine is, the thermostat might be stuck closed. Avoid driving without a thermostat to prevent negative effects on emissions and fuel economy due to the computer staying in open loop mode. If the lower radiator hose is hot, indicating proper coolant flow, consult the troubleshooting guide for cooling system diagnosis. To replace the thermostat, remove the battery and drain the cooling system, potentially saving and reusing the coolant if it's in good condition. Depending on the model year, disconnect the electrical connector or ground wires from the thermostat housing. Unscrew the thermostat housing cover bolts, tap the cover if stuck, and note the thermostat's orientation before removing it. Clean the housing surfaces, install a new seal aligned with the jiggle valve, and position the new thermostat in the housing without sealant, ensuring proper alignment.