Some of the symptoms of a bad thermostat in a car can be seen when you start experiencing poor engine performance. For example, your vehicle may take longer to warm up or overheat unexpectedly.
Vehicle manufacturers have a recommendation as to how often you need to replace your thermostat. This car maintenance task happens in every 100,000 miles.
The role of the thermostat is regulating temperature levels for optimal engine performance. However, it develops issues that arise over time.
Furthermore, the thermostat detects when the engine warms up and opens to allow coolant to flow through the engine. Hence facilitating an ideal operating temperature.
If the dashboard temperature gauge changes, it’s an indication that the thermostat is functioning correctly.
Various symptoms that affect your car’s functionality arise when your car’s thermostat malfunctions. For example, coolant leaks and the temperature gauge will constantly running hot.
Recognizing these signs can help you diagnose and promptly address any problems with your car’s thermostat. This will maintain its longevity and ensure a hassle-free driving experience.
How many thermostats does a car have?
Manufacturers of most cars install only one thermostat. However, some high-performance or luxury vehicles tend to have multiple thermostats.
This is appropriate given the role of the thermostat in engine temperature regulation. Therefore, high performance vehicles require more temperature regulation mechanisms.
Because their engines produce a lot of power which in turn generates a lot of heat. The number of thermostats in a car depends on the car’s design and cooling system.
What are the different types of thermostats?
The operation of each type of thermostat tends to vary. However, they all serve the same purpose of controlling the flow of coolant.
Hence maintaining optimal engine temperatures, preventing overheating and ensuring efficient engine performance.
These are the types of thermostats, the traditional wax pellet design, bellows mechanism, electronic sensors, and dual-stage functionality.
1. Wax pellet thermostat.
This is the most common type of thermostat installed by manufacturers in cars. Some refer to it as a wax element thermostat.
Components of a wax pallet thermostat.
It consists of the a wax pallet and valve which aid its function of controlling the flow of coolant through the radiator. In order to regulate the engine operating temperature.
a). Wax pellet.
This is a wax-filled chamber that expands and contracts with engine temperature changes. The special wax is suitable because of its predictable and consistent thermal expansion properties.
b). Valve.
The valve is the part of the wax pallet thermostat that controls the flow of coolant. An increase in engine temperature levels causes the wax filled capsule or pellet to expand.
Hence exerting pressure on the valve which causes it to open for coolant to flow. On the contrary, when the wax contracts it closes the valve and restricts coolant flow.
2. Bellows thermostat.
This thermostat has two different metals that are bound together. They tend to expand and contract at different rates when subjected to temperature fluctuations.
This thermostat utilizes a sealed metal bellows and operates based on the principle of differential thermal expansion.
Components of the bellows thermostat.
Some people refer to this thermostat as a bimetallic thermostat. Here are some of its components.
a). Bellows.
This is the basic feature of the bellows thermostat. They are two metal strips of different types. These metals have different coefficients of thermal expansion.
b). Rod or spindle.
One end of the bellows attaches to the rod or spindle. They act as a connection from the bellows to the thermostat housing and valve.
c). Valve.
The valve connects to the bellows on one end. Automotive cooling system valve opens and closes when the bimetallic strip expands or contracts due to temperature changes.
Hence regulating the flow of coolant through the radiator and engine.
3. Electronic thermostats.
This is another commonly used thermostat in modern vehicles. It relies on sensors and electronic controls to monitor and adjust coolant flow.
Components of electronic thermostat.
They are applicable in various temperature control set-ups. These are the components that facilitate their functionality.
a). Temperature sensor.
The sensors detect the current temperature and convert temperature changes into electrical signals. Afterwards, these signals determine the coolant flow rate.
b). Microprocessor or microcontroller.
Once the sensor generates the electronic signals, it transfers them to the microprocessor. Next, it processes this temperature data to control the heating or cooling equipment accordingly.
c). Programming options.
The programming capabilities of electronic thermostats allow users to set different temperature profiles. Therefore, enhancing energy efficiency.
4. Dual-stage thermostats.
This thermostat has two stages or settings for regulating coolant flow. Therefore, they offer more precise temperature control and energy efficiency.
Additionally, they can switch between high-stage and low-stage temperature ranges depending on engine conditions. Unlike the single-stage thermostats.
Components of the dual-stage thermostats.
The following are some of the components that enable the dual-stage thermostats to function.
a). Two-stage heating or cooling.
This is a feature that is common when the dual-stage thermostats are used in a heating ventilation and air conditioning (HVAC) system. This component allows for both heating and cooling properties.
b). Temperature differential.
This component allows for a difference to be there between the temperature setpoint by the user and the actual temperature.
c). Energy efficiency.
During the use of the HVAC system, dual-stage thermostats allow users to choose the low-stage setting. This helps reduce energy consumption which is both cost-effective and environmentally friendly.
Roles of the thermostat.
The thermostat in a car is very useful in ensuring that the engine operates at a normal temperature. That’s based on its role as one of the cooling system components.
When engine temperature levels are regulated it maintains optimal engine performance. Furthermore, temperature regulation prevents potential damage.
Here are the key functions of a car thermostat:
1. Regulates coolant flow.
Above we have mentioned that the thermostat plays a role in maintaining an optimal engine temperature. It does so by controlling the flow of coolant through the engine.
Therefore, this ensures that the engine operates at its ideal temperature range.
2. Improves fuel efficiency.
Fuel is used in the combustion process to produce power in the engine. For this to be possible, the engine has to reach its operating temperature quickly.
When this temperature is achieved, the thermostat opens to allow coolant flow into the engine. This sustains the temperature level which promotes better fuel combustion and reducing fuel consumption.
Therefore, a properly functioning thermostat helps improve fuel efficiency by ensuring efficient combustion.
3. Prevents overheating.
The thermostat plays a key role in preventing overheating. whereby, it monitors the engine temperature level and adjusts coolant flow accordingly.
If the engine gets too hot, the high temperatures cause the thermostat to open up. Hence allowing more coolant circulation through the engine.
Coolant flows from the engine to the radiator for the purpose of dissipating excess heat. Hence preventing potential damage that comes from an overheated engine.
4. Protects against engine damage.
When the engine becomes too hot, this heat can cause damage to some parts. When the thermostat senses that the temperature has gone extremely high, it increases the coolant flow.
Then the thermostat keeps monitoring the engine temperature. This regulates temperatures and prevents extreme temperature fluctuations.
If these fluctuations are not checked, they can lead to warping or cracking in critical components like cylinder heads or engine blocks.
Car thermostat parts.
The main components of a car thermostat include the housing, valve, spring, and sensing element.
This knowledge of its various parts can be helpful during identifying any issues and working towards potential solutions. For example, thermostat replacement or repairing specific parts.
problems with a car’s thermostat affect other related systems. For example, the heater core. In the case of malfunctioning thermostat parts your vehicle will be experiencing some symptoms.
For example, overheating, inconsistent cabin temperature, or even coolant leaks.
- Housing.
The thermostat housing encloses all the internal components of the thermostat. Its role is providing protection and support.
- Valve.
Secondly, the thermostat valve is a crucial part that opens and closes to control the flow of coolant based on temperature changes. It regulates the amount of coolant circulating to the radiator and through the engine.
- Spring.
Thirdly the thermostat spring plays a role in maintaining valve tension for the purpose of opening and closing. It ensures that the valve adjusts position, operates smoothly, opens and closes effectively.
- Sensing element.
The thermostat sensor is a sensing element that detects changes in engine temperature levels. Afterwards, it triggers the valve to open or close for coolant to flow accordingly.
Thermostat car AC.
The car’s heating ventilation and air conditioning system (HVAC) is separate from its engine cooling system. Therefore, the thermostat does not directly control AC functions.
However, a malfunctioning thermostat will indirectly affect the AC performance. The operation of the car’s air conditioning system is independent from the engine cooling system.
The thermostat’s role is primarily regulating the engine’s temperature. However, it indirectly influences the AC’s efficiency.
Whereby the engine’s temperature affect the HVAC system. Therefore, a faulty thermostat will lead to irregular engine temperatures.
Hence affecting the overall performance of the air conditioning system. For example, in cases where the AC doesn’t blow cold air.
Here a malfunctioning thermostat will cause the air conditioner to blow warm or hot air instead of cool air.
Because a stuck thermostat valve prevent the engine from reaching optimal operating temperature. Hence resulting in reduced AC performance.
Therefore, inspect both the cooling system and thermostat when experiencing issues with your car’s AC.
Ensure optimal functioning of both your car’s cooling and air conditioning systems through regular maintenance and timely replacement of a bad thermostat.
What causes a thermostat to fail?
The crucial role of a car’s thermostat is regulating the engine temperature level. However, like any other engine component, it is susceptible to failure.
Car owners can diagnose and address the issue of a malfunctioning thermostat promptly if they understand the causes.
1. Wear and tear over time.
Firstly, the thermostat mechanism deteriorates due to continuous exposure to high temperatures. Secondly, constant cycling back and forth during opening and closing also have a negative effect over time.
The Spring is one of the internal components that suffers damage over time. Due to repeated expansion and contraction causing it to weaken and leading to eventual failure.
2. Rust or debris buildup.
The thermostat is directly linked to the cooling system. Rust or debris accumulate within the cooling system when you neglect to perform a coolant flush.
Their accumulation hinders the proper functioning of the thermostat. Whereby, the thermostat valve is stuck open or closed due to a lot of buildup.
Hence resulting in inaccurate temperature control.
3. Incorrect installation or poor maintenance practices.
DIY installation of the thermostat is highly discouraged if you don’t have the skills and the manufacturer’s instructions. Because improper installation of a new thermostat contributes to its premature failure.
Additionally, neglecting routine cooling system maintenance tasks also causes thermostat failure.
4. Coolant quality.
Each vehicle should use the type of coolant that’s recommended by manufacturers. Using the wrong coolant leads to issues within the cooling system parts including the thermostat.
The coolant quality depreciates over time that’s why it is not recommended to recycle coolant for a long time.
Therefore, the wrong coolant and neglecting coolant changes results in corrosion, dirt and deposit buildup in the thermostat housing.
Furthermore, there are engine coolants that come with additives for better cooling system performance.
Using incompatible additives and the wrong type of coolant can lead to thermostat problems.
5. Overheating.
Continuous exposure of the thermostat to high temperatures causes its components to degrade or malfunction.
There are situations when the car is running hot but not overheating caused by cooling system issues.
This exposes the thermostat to high engine temperatures which might interfere with its sensing element.
What does a bad thermostat look like?
The components of a thermostat will exhibit different characteristics when they become faulty. For example, the thermostat valve may be stuck closed or open.
There are different reasons why the thermostat components becomes faulty. Those are mentioned above.
1. Physical damage or corrosion on external surfaces.
The presence of physical damage on the external parts of a thermostat result from bad installation or manufacturer defects.
Furthermore, accumulation of corrosion on its surface resulting from coolant issues is also a clear indication of a faulty thermostat.
Damage includes cracks, rust, or signs of wear and tear. These disrupt the proper functioning of the thermostat and lead to various issues in the car’s cooling system.
2. Faulty valves that do not open or close properly.
Faulty thermostat valves fail to open or close as they should. When thermostat valve is stuck open or closed, it fails at regulating the flow of coolant through the engine.
Hence resulting in overheating or insufficient cooling, causing potential engine damage.
3. Leaking coolant around the thermostat housing area.
The thermostat housing shows signs of malfunctioning when there is coolant leakage around it. A faulty water pump is among the things that cause coolant leaks.
However, coolant leaks around the thermostat housing result from worn-out gaskets or seals within the thermostat assembly.
This situation tends to disrupt temperature regulation and negatively impact engine performance.
Signs of a bad thermostat.
symptoms of a bad thermostat in a car will arise within the vehicle’s cooling system. The following are some of the common signs to watch out for that point towards a bad thermostat.
1. Increased fuel consumption and poor economy.
A malfunctioning thermostat can cause the engine to run hotter than normal. This causes an imbalance in the combustion process.
When fuel doesn’t burn fully, it results in increased fuel consumption. During this occasion you will noticea sudden decrease in gas mileage.
Hence more frequent visits to the gas station. There are many reasons why the car consumes more fuel and a bad thermostat is one of them.
a). Engine running too cold.
The engine may fail at achieving normal operating temperature when you have a bad thermostat in a car. When the engine runs too cold, it will lead to inefficient fuel combustion.
This is because of a disruption of the optimal fuel-to-air ratio. Hence affecting overall fuel economy.
Monitoring fuel efficiency is crucial to identifying potential thermostat issues. You can monitor fuel efficiency by tracking how much fuel is being used over a certain distance or period of time.
2. Overheating and heating system problems.
A failing thermostat in a car affects the engine’s temperature regulation. Furthermore, it leads to several symptoms which affect the heating system performance.
a). Engine overheating.
A failing thermostat causes the valve not to open or close properly. This leads to the engine overheating due to disrupted coolant flow.
Overheating can be indicated by a rise in the temperature gauge beyond normal levels. Furthermore, in extreme situations you will notice steam coming from under the hood.
b). Poor heating system performance.
Coolant flows through the heater core and a faulty thermostat interferes with this process. Which leads to insufficient heat from the car’s heating system.
Therefore, causing a lack of warm air blowing from the vents even when the heater is turned on.
c). Temperature fluctuations.
The thermostat detects engine temperatures and displays the reading on the temperature gauge. When there are sudden fluctuations in temperature while driving the thermostat could be the problem.
In this case you will notice that your car quickly goes from overheating to overcooling or vice versa.
3. Coolant leaks and loss.
Coolant leaks or loss from the car’s cooling system due to a faulty thermostat are a result of damaged seals or gaskets around the housing.
Check whether there are puddles beneath your vehicle to conclude that you’re loosing coolant. Additionally, you can tell if you have coolant leaks when you frequently need to top up the coolant reservoir.
Loss of coolant due to a faulty coolant reservoir cap or other reasons affects the car’s cooling system performance.
Repairs to prevent coolant leaks cause by a faulty thermostat will involve replacing seals, gaskets, or the entire thermostat assembly.
You should promptly address coolant leaking because it poses environmental concerns.
4. Incorrect temperature gauge readings.
Once the thermostat reads engine temperature, it displays them on the temperature gauge on your dashboard. Therefore, incorrect temperature gauge readings is a telltale sign of a bad thermostat.
You will notice that the gauge needle consistently stays at either extreme hot or extremely cold. The malfunctioning thermostat will lead to inaccurate engine temperature readings on the gauge.
These readings will be wrong even when the engine is operating normally. Closely monitoring temperature changes will help to identify potential thermostat issues.
The temperature gauge will display unusually high or unusually low temperatures. Consistently low temperatures suggest that your engine isn’t reaching the optimal operating temperature.
Hence affecting fuel efficiency and the overall performance. Detecting potential overheating issues and other vehicle’s cooling system problems is it difficult with an unreliable temperature gauge.
5. Rumbling or knocking noises from engine.
Any faulty component of the cooling system that may lead to improper coolant circulation can often cause these sounds.
However, when the cause is a faulty thermostat the problem is usually coming from a malfunctioning valve.
it’s important to promptly address them for proper diagnosis and repair. Seek a professional mechanic to diagnose the issue and replace the thermostat.
a). Knocking sounds.
When the thermostat is malfunctioning, it disrupts the flow of coolant. Meaning that the engine struggles to maintain optimal temperature levels.
Therefore, this may lead to overheating and the engine will produce knocking sounds.
b). Rumbling noises.
When coolant is not circulating properly through the engine block it leads to development of hot spots develop within the engine.
This causes uneven combustion and vibrations which are heard as rumbling noises.
6. Check engine lights and codes..
Dashboard warning lights are codes in the on board computer that help to warn the driver that something is wrong within the system.
There are several symptoms that indicate that point to a bad thermostat in your car and a dashboard warning light is one of them.
a). Check engine light.
Given the crucial role of the thermostat in regulating engine temperature, its malfunction, can trigger this warning light.
However, there are several causes for this warning light to be illuminated. In order to diagnose what is causing it, you need a diagnostic tool which can read and interpret the codes for you.
Alternatively, if you don’t have access to a diagnostic tool and you suspect a faulty thermostat it is highly recommended to undertake testing.
Bad thermostat housing symptoms.
The thermostat is part of the vehicle’s cooling system. It works to regulate engine temperatures by controlling the movement of coolant in the cooling system and through the engine.
The thermostat housing encloses all the internal parts of the thermostat. Corrosion, dirt buildup and overheating are some of the reasons for a bad thermostat housing.
Therefore, this can cause various symptoms in a car. Here are some signs to watch out for:
1. Damaged housing may lead to coolant leaks.
The thermostat housing suffers physical damage which can result in coolant leaks. The damage results from cracks or fractures in the housing itself.
When the coolant leaks due to a faulty thermostat housing, you will find puddles or drips of coolant underneath your car near the engine area.
a). Leaking coolant around the housing area.
Leaking coolant around the housing area is another sign of a thermostat housing problem.
2. Corrosion on the housing surface indicates potential issues.
The thermostat housing may develop corrosion on its surface over time. Corrosion happens as a result of recycling coolant for a long time which changes the coolant PH.
Corrosion weakens the structure of the housing and potentially leads to problems with the functioning of the thermostat.
Have the thermostat inspected by a mechanic if you observe rust or other signs of corrosion on the housing.
3. Overheating.
A radiator cap leaking coolant is one amongst many causes of engine overheating. The reason for overheating in this case is due to a low amount of coolant in the cooling system.
This is where the thermostat housing comes in. Such that, if the housing is faulty, it causes the valve to either become stuck open or closed.
This interferes with coolant flow leading to engine overheating. An overheating engine can cause damage to the engine components, so it’s crucial to address this issue promptly.
4. Inconsistent temperature.
Engine temperature is displayed on the temperature gauge displayed on the dashboard. A malfunctioning thermostat housing will interfere with temperature reading.
Hence leading to inconsistent engine temperatures. When the thermostat housing is faulty, your engine temperature gauge fluctuates between hot and cold.
Additionally, you will notice that the engine takes a long time to reach its optimal operating temperature.
5. Poor engine performance.
Optimal engine performance depends on the temperature level being right. However, a malfunctioning thermostat housing will cause the engine to operate at temperatures that are too high or too low.
Hence impacting engine performance which results in reduced engine power, poor fuel efficiency, and increased emissions.
How to test thermostat car step by step.
There are two main methods of testing the thermostat. These are;
- Visual inspection.
- Boiling water test.
- Multimeter test.
Start by assembling the right tools for the type of test you intend to undertake. Afterwards, ensure that the engine is completely cool before starting the process.
This will ensure that you avoid any burn injuries that can be caused by the hot coolant. Protect yourself by wearing safety goggles and gloves.
1. Locate the thermostat.
Different manufacturers install the thermostat in varying places. Therefore, you will have to consult your vehicle’s manual to see where its located in your engine.
However, most engines have the thermostat connected to the upper radiator hose.
2. Drain coolant.
Drain some coolant first to prevent spills before you start removing the thermostat. Next, loosen the hose clamp, then place a container to catch the coolant before detaching the upper radiator hose.
Some coolant will drain into the container to give way for visibility of your thermostat.
3. Remove the thermostat.
Once the thermostat is visible, get a screw driver or something to unscrew the bolts that hold the thermostat housing in place. This will loosen the thermostat housing and allow you to remove it.
4. Visual inspection test of the thermostat.
A visual inspection will allow you to identify any signs of physical damage and deterioration. For example, warping, debris, sludge or corrosion.
These are an indication of a faulty thermostat. Therefore, immediate thermostat replacement is highly recommended to avoid problems.
5. Boiling water test.
Put water in a small pot and place it on fire or use other commonly used means of boiling water. Ensure that you heat the water up to when its at a rolling boil or nearly boiling.
Next, fully submerge the thermostat housing into the boiling water. At this stage the water should keep boiling.
Observe how the thermostat behaves. If its working, the thermostat should start to open as the temperature rises.
The thermostat has a rated opening temperature which is labeled on it. Use a thermometer to measure the temperature at which the thermostat starts to open.
Your thermostat is faulty whereby it doesn’t open or it opens up at the wrong temperature.
6. Multimeter test.
A multimeter is a tool used in various tests within the vehicle engine system. For example, testing car battery voltage. Ensure that the multimeter is in a good condition for you to receive the correct diagnostics.
- First ensure that the automotive multimeter is set to the resistance (ohms) setting configuration.
- Locate the thermostat’s terminals and use the multimeter to measure the resistance.
- When the measurement is high resistance, it means it’s a closed thermostat.
- Next, conduct the boiling water test until the thermostat opens up. Do so with the multimeter still attached to the thermostat terminals.
- Resistance decreases significantly while the thermostat opens up in the hot water
- If multimeter reading doesn’t indicate a resistance drop its likely that the thermostat is faulty.
Your understanding of the symptoms of a bad thermostat in a car, will help you to diagnose whether your car’s thermostat is functioning properly or not.
For example, increased fuel consumption, overheating problems, coolant leaks, incorrect temperature gauge readings, and unusual engine noises.
Regular thermostat maintenance and timely replacement when its faulty are essential for the smooth operation of your vehicle engine.
Consult with a professional mechanic if you notice any of the mentioned symptoms or suspect a bad thermostat in your car. The professional mechanic can accurately diagnose and fix the issue.
Can I drive my car with a bad thermostat?
When you realize that your vehicle’s thermostat is faulty, it’s highly discouraged to continue driving it in that condition.
A malfunctioning thermostat can lead to severe engine overheating damage. Avoid driving your car until the thermostat issue has been resolved.
Replacing the faulty thermostat is the best solution for thermostat problems.
Are there any preventive measures I can take to avoid a bad thermostat?
Regularly maintaining your car’s cooling system components by performing coolant flushing and replacement. Additionally, follow the manufacturer’s recommendations during these maintenance activities.
This can help to prevent thermostat issues.
