Occasionally, your vehicle's thermostat will go bad and either function poorly or stop functioning. When this happens, your operating temperature will suddenly start to increase, which can lead to severe engine damage if you don't take care of it. A "quick fix" for a bad thermostat can be to simply remove the thermostat, allowing coolant to flow unregulated into your engine. This might cause your engine to operate less efficiently, but it still will allow you to drive the car without risking engine damage.
Lift the vehicle off the ground with a jack, and settle it onto jack stands.
Place a bucket underneath one of the lower coolant hoses attached to your radiator. You will need to drain the coolant from your radiator in most cases before attempting to remove the thermostat from the engine.
Use a flat-blade screwdriver to loosen the hose clamp securing the lower coolant hose to the radiator, then slowly work the hose off. Position the bucket to catch the coolant as it comes out of the radiator.
Locate the thermostat housing on your engine block. This can be done by following one of the two large hoses -- one on top, the other on the bottom -- on your radiator. The thermostat housing will connect to the coolant hose and is bolted to your vehicle's engine block.
Use a ratchet and socket set to loosen and remove the bolts securing the thermostat housing to the engine block. Depending on your vehicle, you might need to remove other parts before you can reach the thermostat housing. You might also need to remove the coolant hose to access the bolts.
Remove the thermostat housing from the engine block, then pull the thermostat out of its setting and discard it.
Secure the thermostat housing back to the engine block, and reconnect the hoses and other parts you might have disconnected during this process.
Refill the radiator with the coolant you drained in step 3, then lower your vehicle off the jack stands.
Occasionally, the thermostat will be in or behind your vehicle's water pump. Consult your vehicle's documentation before performing the operation to ensure you know where the thermostat is.