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Home » 6 Symptoms of bad car thermostat – Causes and replacement cost

6 Symptoms of bad car thermostat – Causes and replacement cost

Bad car thermostat

When the heat in a car is not regulated properly, the engine will overheat. This can cause major damage to your engine and other parts of your car.  Most people do not know the part of the car that regulates this function. Your thermostat is responsible for this, and if you have a bad car thermostat, your car will surely misbehave. This page will give an answer about the symptoms of a bad thermostat in a car.

A bad car thermostat is one that doesn’t work properly. There are many different types of thermostats, but they all have one thing in common: they regulate the flow of coolant through your engine. If your thermostat fails to operate correctly, you will notice that your car’s temperature gauge is higher than normal or stays on one side of the scale for an extended period of time.

This is because the thermostat has shut off the flow of coolant through your engine, which prevents it from cooling down properly. So, if you’re noticing weird behavior from your car’s heating system, there’s a good chance that it’s because of a bad thermostat.

Bad car thermostat

How to tell if a car thermostat is bad?

If you’re having trouble with your car’s thermostat, it might be time to replace it. Here are some signs that will help you figure out if your thermostat needs replacing:

1. Your car is overheating

If your car is overheating, it could be because of a bad thermostat. Overheating can cause damage to the engine and other parts of the car.

2. The engine is running too hot

If the temperature gauge on your dashboard goes up past normal levels, there may be something wrong with your thermostat. If the gauge stays high when you turn off the engine and then go back on again, it could mean there’s a problem with your thermostat.

3. There are leaks around where the hose connects to your engine

If you notice any moisture under or around where the hose connects to your engine, this may also be a sign that there’s an issue with your thermostat (or another part).

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What does a bad car thermostat look like?

It’s not hard to tell if you have a bad car thermostat or some symptoms of bad thermostat in car occuring. The first thing to look for is whether caryou are running hot or cold. If it’s running too hot, then it might be time to get a new thermostat.

If the thermostat is stuck open or closed, then that means it’s not working properly. You’ll want to replace your thermostat if this happens because it could cause other problems with your engine.

If the thermostat is cracked or broken, then it needs to be replaced immediately because this can cause major damage to your engine.

If you’re still unsure about whether or not your thermostat needs replacing, then take some time and check out these signs that indicate something isn’t right with your car:

  1. Your engine runs hotter than normal.
  2. The battery light flashes on and off.
  3. You hear a rattling noise coming from under the hood.

Does a bad thermostat affect the air conditioning in a car?

Yes, a bad thermostat will affect the air conditioning in your car. The thermostat controls the temperature of the coolant in your engine, which is a mixture of water and ethylene glycol (an antifreeze).

When the thermostat is working correctly, it regulates how hot the coolant gets. The coolant passes through a radiator before it is circulated back into your engine to keep it at an ideal temperature for operation. If the coolant gets too hot or too cold, it could damage your engine’s components.

Therefore, if there’s something wrong with your thermostat, it won’t be able to regulate the temperature of your engine properly. This means that your car may overheat when you’re driving on long trips or during high temperatures outside, which can cause damage to other parts inside as well.

Can a bad thermostat cause a car to overheat?

A bad thermostat can cause a car to overheat, but it’s not the only thing that could be causing an overheating problem.

Your car’s thermostat is basically a valve that opens and closes as needed to regulate the temperature in the engine. If the thermostat isn’t functioning properly, it can allow coolant to flow through it at all times and prevent hot coolant from circulating around the engine block. This will cause your engine to overheat.

Can you drive a car with a bad thermostat?

Yes, you can drive a car with a bad thermostat. But there are certain things you should check before deciding to continue driving your car.

If you notice that the temperature gauge is staying at the middle or high end of the scale, the engine is overheating, or your car has been running hot for some time, then it’s probably best to have it checked out by a mechanic.

However, if none of those things is happening and your vehicle is still running smoothly with no issues, then it may be okay to keep driving it.

It’s important to remember that driving with a bad thermostat will put more strain on your engine and cause it to use more fuel than normal. So, even though you might be able to make it home safely when everything is working properly, there’s no guarantee that this will always be the case once you start experiencing problems due to excessive heat build-up.

Will a bad thermostat make your car run rough?

Yes, a bad thermostat can make your car run rough. A thermostat is a small part inside your engine that regulates the temperature of the coolant fluid and keeps it at a constant temperature. If the thermostat fails, the coolant will not be able to reach a proper operating temperature, which can cause many issues with your vehicle.

When an engine is running poorly, and you suspect that something might be wrong with your thermostat, there are a few things to check first. These include:

The radiator cap:

Make sure that you have a new one installed on both your radiator and expansion tank. If they are old or damaged, they can cause problems with the cooling system by letting air into the system or not releasing enough coolant when needed.

Air filter:

Make sure that this isn’t clogged up with too much dirt or dust, as this will make it harder for air to flow through properly.

Fuel filter:

Replace this if you haven’t done so recently (every 30k miles). It should help improve fuel economy as well as protect against costly repairs down the road from dirty fuel getting into other parts of your engine (like spark plugs).

Will a bad thermostat cause my car not to start?

Well, a bad thermostat definitely won’t help your car start, but it’s unlikely to be the reason it’s not starting.

The most common cause of an engine that won’t start is a dead battery. If you’ve already checked your battery, or if it’s not dead, then the next thing you should check is if the fuel pump is working. If there are no other problems with the engine and it still won’t start, then there could be something wrong with the ignition (the part that sparks up when you turn the key).

If none of these things are happening, then it’s possible that there’s something wrong with your starter or alternator. These are more expensive fixes than replacing a thermostat would be, and they can cost thousands of dollars if they’re beyond repair.

4 Cause of bad car thermostat?

The most common causes of bad car thermostats are:

1. Age

Thermostats have an average lifespan of about ten years, but they can fail sooner than that if they have been exposed to high temperatures or other harsh conditions (such as corrosion).

2. Poor maintenance

If you don’t perform regular maintenance on your vehicle (such as changing the oil), it may be difficult for you to detect when something small like your thermostat needs replacing before it becomes a large problem like overheating or loss of coolant from your engine block.

3. Leaking coolant

This is one of the most common causes of car thermostat failure. This can happen if there is any kind of leak in your cooling system, which means that the coolant isn’t circulating properly and doesn’t reach all parts of the engine, including where it needs to go for proper heat regulation.

4. Improper installation

If you didn’t install your thermostat properly when you replaced it or did not use new gaskets and seals when installing it, then it may not seal properly against its housing and could leak coolant into other parts of your engine compartment, causing corrosion on electrical connections.

What are the bad thermostat symptoms?

If your thermostat isn’t working properly, it might be time for a repair or replacement. Here are some common problems that could indicate the need for a new thermostat:

1. Higher temperature reading

A temperature gauge reading higher than normal is one of the many bad thermostat symptoms. A thermostat controls the temperature in your vehicle and works with other parts so that your vehicle operates at its optimal temperature.

When it comes to the temperature gauge reading higher than normal, this may mean you need a new thermostat. The thermostat helps control the heat in your truck or car by controlling when heaters turn on and when they turn off.

2. Coolant leakage

Coolant leakage can be an ominous sign of a bad thermostat. Your thermostat regulates the speed at which coolant flows through your vehicle’s engine and safely disperses heat. In fact, all sorts of problems can happen when your thermostat malfunctions: overheating, loss of power, air conditioning failure, and more.

When your car’s coolant starts to leak, this can be a potentially dangerous situation. Leaking coolant from the radiator may drip onto hot engine components and ignite combustion. This could lead to major damage and may even be life-threatening.

3. Rumbling noise

Rumbling noise is a symptom of a faulty thermostat. This can be caused by the failure of any one or more components in the system, including the part that senses the temperature, controls the heat output, and then operates a solenoid valve to release coolant into your system.

A clogged radiator may also cause this symptom as it restricts coolant flow. If your thermostat begins to rattle and shake in operation, contact a certified mechanic immediately to remedy this problem before it becomes worse.

4. Overheating engine

Overheating can be caused by overheating the engine, which in turn is caused by the thermostat remaining open while the engine is running. Heat builds up and becomes trapped inside of the engine, causing damage from heat buildup.

The best way to avoid overheating is to perform regular maintenance on your car, including replacing a bad thermostat.

5. Heater fluctuation

Heater fluctuation is the main symptom of a bad thermostat. Sometimes a car will experience fluctuations in air temperature that can make the heater blow hot and cold. This happens because a bad sensor or computer malfunction allows for different levels of humidity to pass through the heating system, even when set at a constant temperature.

So, if your heater seems like it’s blowing warm or cold air randomly or isn’t keeping you warm at low speeds, this could be your problem.

6. Temperature fluctuation

A temperature fluctuation in your car is a clear sign that something is wrong with your thermostat. You need to find out what exactly it is so that you can fix it before your car overheats and ends up in an accident.

The temperature in your vehicle can change at any time and without warning. This is a normal occurrence and can cause the engine temperature gauge to fluctuate with it. While fluctuations are normal, it can be scary and confusing for a novice driver.

It is important to be familiar with the symptoms of a bad thermostat so that you know when you should get your vehicle checked out.

Car thermostat replacement cost

The cost of replacing your car thermostat depends on the type of car you have. In general, though, the job can be done for around $150 to $200.

The price of a new thermostat will vary depending on what kind of vehicle you drive. For example, if you have an older model car or one with a small engine, it may only cost around $100 to $150 to replace the part. More expensive models can cost up to $400 or more.

You can save money by doing some research before taking your vehicle into a shop for repairs or replacement parts. You may find that there are less expensive alternatives available online that will suit your needs just as well as an expensive brand name product would.

Will a bad car thermostat damage the car?

Yes, a bad car thermostat can damage the car. If your car is overheating, it’s time to check your thermostat. If it’s not working properly, the engine will never get back to its ideal operating temperature, which can lead to some major problems.

The first thing to check is whether or not your coolant needs to be replenished; if so, that’ll fix the problem right away, and there’s nothing else you need to worry about. But if you’ve checked that and everything else seems fine, then it’s possible that your thermostat has gone bad.

You’ll want to consult a professional mechanic for this kind of work because they will be able to test your thermostat and tell you whether or not it’s broken without causing any further damage, which means no more expensive repairs down the road.

Car thermostat replacement cost

Car thermostat replacement cost can vary depending on the vehicle, but it’s usually around $100 to $200.

The thermostat is a small, plastic device that regulates how hot or cold your car gets and is usually located in an engine compartment. It’s important to replace your thermostat if it’s broken or malfunctioning because your engine won’t run efficiently, and you could end up damaging other parts of your engine.

Most people find that their car thermostat needs replacing when they start seeing problems like overheating or poor performance.


Your car needs a quality thermostat to work optimally. If the thermostat is bad, then the car is likely to get damaged in the long run. There are many bad car thermostats that you need to know to prepare you ahead of what is likely to happen.

You need to know that a bad thermostat can cause damage to your car, and that is the reason you need to keep it in good condition at all times. Ensure you take your car for inspection whenever you notice any sign of a bad thermometer.