How to Unstick a Thermostat in a Car? Avoiding Car Overheating Issues

To unstick a thermostat, it is better to replace the stuck thermostat. If you want to replace the thermostat, identify the thermostat housing, drain the coolant and remove it from the thermostat assembly, examine and position the new thermostat, install it, and then refill the coolant. Although you can fix a stuck open thermostat, getting a new one is much less of a hassle. 

If you want to find out more about thermostats stuck in the car, then keep reading this article. 

Table of Contents

• How to Replace a Stuck Thermostat in a Car?
  • Identify the Thermostat Housing
  • Drain the Coolant and Remove the Thermostat Assembly
  • Examine and Position New Thermostat
  • Install New Thermostat
  • Refill Coolant and Bleed System
• How to Fix a Stuck Open Thermostat
• How Can You Avoid a Thermostat Stuck Closed?
  • A thermostat stuck open:
• How Can You Avoid a Stuck Open Thermostat?
• How to Detect a Stuck Thermostat?
• What Are the Signs of a Bad Thermostat?
• How Do I Know if My Thermostat is Stuck Open or Closed?
• Can a Stuck Thermostat Fix Itself?
• Can You Drive with a Bad Thermostat?
• Frequently Asked Questions (FAQs):
  • Can you Drive a Car Without a Thermostat?
  • Can a Car Overheat Without a Faulty Thermostat?
  • What is the Operating Temperature of a Thermostat?
• Conclusion

How to Replace a Stuck Thermostat in a Car?

Once again the best bet for you to fix a stuck thermostat in a car is to replace it with a new one. We are going to cover the steps in detail. 

Identify the Thermostat Housing

Follow the lower radiator hose to locate the thermostat housing on your vehicle’s engine. The housing is easily identifiable by its prominent bolts securing it in place.

Drain the Coolant and Remove the Thermostat Assembly

Place a pan under the thermostat housing to catch any coolant, then use a 12-millimeter wrench to remove the bolts. Loosen the clamp on the radiator hose and move it out of the way to access the thermostat assembly.

Examine and Position New Thermostat

Inspect the old thermostat, noting its orientation. When installing the new one, ensure the short end faces the hose and the deep end faces the engine. Check for a toggle switch on the thermostat; position it upward for efficient air release.

Install New Thermostat

Insert the new thermostat into the housing with the rubber gasket. Place the cover on top, secure it with bolts, and tighten them securely. Slide the radiator hose back into position and use pliers to reattach the clamp.

Refill Coolant and Bleed System

Pour coolant into the radiator, start the engine, and turn the heat to maximum. While the engine warms up, add coolant until it’s warm, and all air is purged from the system.

If you prefer a visual demonstration of the process then check this

How to Fix a Stuck Open Thermostat

If the problem of a stuck open thermostat is detected while driving, stop the vehicle immediately to avoid engine damage. Leave the car on a flat surface and switch it off, allowing the engine to cool down.

Observe the thermostat itself, remove the radiator cap, and after that, disconnect the radiator hoses from the motor. Ensure they are not hot. Replace the thermostat valves.

Pour more antifreeze if it is needed and try to run the vehicle. If the problem continues and the temperature rises, in this case, the thermostat replacement is unavoided.

How Can You Avoid a Thermostat Stuck Closed?

Dirty engine oil can cause the thermostat to become stuck closed, preventing coolant liquid from proper circulation.

We strongly recommend measuring regularly your engine oil level with a dipstick when a car is cold. In case the amount of liquid is not enough, it should be poured.

Additionally, the filter should also be checked in case you are aware of problems. If there is dirt build-up on a filter, the oil filter should be changed without changing the oil, though changing the oil is recommended with an oil filter.

A thermostat stuck open:

When the car is cold, and you start it, the thermostat is closed, only allowing cooling fluid to get through the engine and the heater core in case the heater is on. If the problem is not with a plugged heater core, the overheating issues might be caused by an open thermostat.

The most common reason for a stuck open thermostat is corrosion. Within time, the corrosion can become bigger and avoid the appropriate opening of a thermostat.

When a thermostat is stuck open, it means there is no possibility to accumulate the coolant level. In this case, the engine warms with difficulties. Without proper warming, the engine temperature is also low, and this leads to a car idling in cold air conditions.

The common issue with a bad thermostat is that the temperature gauge indicates various numbers, approximately 220 – 230 degrees Fahrenheit.

Avoid operating your vehicle when you notice a car’s thermostat is stuck open. Thermostat replacement is the only possible solution in this case.

How Can You Avoid a Stuck Open Thermostat?

When the thermostat is stuck open, you can avoid this issue by regularly flushing your cooling system components. Such washing will remove any built-up corrosion and debris which might lead to a malfunctioning thermostat.

Besides, every time you pour new coolant, ensure it is fresh and of good quality to flush the cooling components.

How to Detect a Stuck Thermostat?

The thermostat stuck closed issue can be fixed by removing the radiator cap or opening the car’s bonnet.

The coolant should be flowing in an open thermostat without the engine leaking. The cooling system does not run while the engine overheating. If the thermostat is in a closed position, it should start flowing within 10-15 minutes. Difficulties in warming the engine cause the stuck closed thermostat.

What Are the Signs of a Bad Thermostat?

In a car, the signs of a bad thermostat are 

• Sudden changes in the engine temperature. It rises and drops suddenly.
• Just like the engine gurgling sound, there will be bizarre changes such as rumbling, boiling, or knocking from the engine
• The engine may either overheat or not reach the optimal heating temperature
• The temperature gauge in the vehicle displays the wrong reading i.e. unusually high or just incorrect data
• Check Engine Light might come on if you are driving a newer car. 

How Do I Know if My Thermostat is Stuck Open or Closed?

The appearance of a “check engine light” is the most common sign of a problem with an erratic temperature gauge engine temperature. To avoid the mechanic’s visit, you might troubleshoot yourself and find the best solution.

If your motor vehicle’s thermostat has blown over the temperature, you will face a stuck thermostat while driving.

In case the coolant doesn’t circulate correctly, this causes high engine temperatures and a car overheats. The thermostat should be replaced.

When the car runs warm, keeping the same temperature, may cause closing the temperature gauge down.

If case the cooling agent is circulating but not sufficiently, it causes problems in cooling the engine. The thermostat replacement is also required.

Can a Stuck Thermostat Fix Itself?

Yes, a stuck thermostat can fix itself. Although rare, in some cases thermostat can stick and then unstick by itself. But, don’t wait for the thermostat to fix itself rather get the thermostat inspected when you find it stuck. If there is a problem then replace the thermostat. 

Can You Drive with a Bad Thermostat?

Yes, you can drive with a bad coolant thermostat. But don’t do that. It will harm your engine in the long run. Since the thermostat helps the engine to work with optimal working temperature. Depending on its temperature, the thermostat closes the cooling fan and prevents the cooling. 

Frequently Asked Questions (FAQs):

Can you Drive a Car Without a Thermostat?

No, there is no possibility to run a vehicle without a thermostat. The temperature controls the cooling fluid in an automobile, and without it, the motor can overheat, and your trip won’t last long but will cost you much.

Can a Car Overheat Without a Faulty Thermostat?

Yes, the car overheats in case of faulty pumps, hoses, and fans. Several issues may cause high temp and make your engine overheat.

What is the Operating Temperature of a Thermostat?

The appropriate operating temperature in the car thermostat is approximately 120 °F. For a proper temperature gauge, coolant has to be sensitive to engine conditions: hot and cold. 

Conclusion

In conclusion, it is better to replace the thermostat rather than unstick it. To detect the problem with a stuck thermostat, you should check the pump and radiator hoses, the heater core issues, and the fan to ensure that a thermostat needs replacement.

To avoid costly engine repair, we advise you to regularly check all the liquids in your car, and in case a thermostat is stuck, replace it immediately.