Maintaining the right temperature is crucial to the well-being of your car.
If your engine overheats, it could cause serious issues with how well your car functions.
Thermostats maintain the temperature of your engine, as well as the temperature inside the car.
How many thermostats does a vehicle have?
We’ll discuss the answer to that question, as well as other important information, such as how the thermostats work.
How Many Thermostats Does A Car Have?
Every car has at least one thermostat.
Cars with climate control have two.
The first thermostat is the one on the engine.
It works to warm your engine up, and then keep it from overheating.
It is located between the engine and the radiator.
The second thermostat in cars with climate control changes the temperature of the air entering the car through the vents.
It’s typically not called a thermostat.
Instead, it’s often referred to as a temperature control sensor.
Because the engine thermostat works independently of the temperature control sensor, when the AC goes out in your car, it doesn’t affect engine temperature.
The opposite is not always true, however.
Why Is the Engine Thermostat Important?
Most car engines today are liquid cooled.
This means that they are cooled by an alcohol-based coolant.
Running an engine generates heat, which, if left unchecked, can cause serious problems for your car.
The cooling system transfers the heat to the coolant using water pumps and hoses.
Then, the hot coolant is moved to the radiator, where it is turned into air that can escape the engine through a cooling fan.
This process is monitored and controlled by the thermostat.
The thermostat is essentially a valve that can open and close depending on the temperature of your vehicle’s engine.
It serves as the barrier between the engine and the radiator.
When your engine is still warming up and the coolant is not hot, the thermostat closes, preventing it from being transferred to the radiator.
The coolant will circulate through the engine until it warms up enough to open the thermostat.
Once the thermostat opens, the coolant is free to cycle through the radiator and back to the engine.
If the engine gets very hot, the thermostat will open all the way, leaving the radiator entirely responsible for preventing the car from overheating.
The thermostat generally opens at around 195 degrees Fahrenheit and is fully open at about 20 degrees above that.
If the thermostat were not in place, the heat in the engine would continually flow into the radiator, preventing your engine from ever warming up.
The restriction of the thermostat also keeps pressure in the engine, which prevents the coolant from boiling.
If the coolant boils, it can overheat and destroy your engine.
What Are Signs Of A Broken Thermostat?
Many cars have a temperature gauge on the dashboard that indicates the temperature of the engine.
When you first start your car, the gauge will point to the coldest setting, because your engine has not warmed up yet.
As you drive, the temperature will rise, and so will the gauge.
It should stop, however, right around the halfway point between hot and cold.
If you see your gauge start to rise past that, it could indicate a problem.
If your gauge begins to fluctuate a lot or gets up to about the ¾ point, your thermostat is likely damaged, and your car could be on its way to overheating.
Another sign of a bad thermostat is leaking coolant.
If your thermostat is stuck in a closed position, the coolant will overflow.
This does not, however, always indicate a problem with the thermostat.
It could be an issue with your radiator or its hoses.
Odd noises coming from your engine are usually cause for concern.
Rumbling, boiling, gurgling, or knocking sounds coming from under the hood could mean your coolant is boiling.
A bad thermostat will also prevent hot air from entering the cabin of your car.
When coolant is transferred between the engine and the radiator, some of it is diverted into the car’s heating core.
The air warmed in the heater core by the coolant is then pushed through your vents when you turn on the fan.
However, if the thermostat is perpetually open, the coolant can’t heat up, causing your heating system not to work.
If the thermostat is stuck closed, coolant can’t flow through the core at all.
This will also prevent the air flowing through your vents from warming up.
What Should I Do If My Thermostat Goes Out?
The simplest answer to this question is to stop driving your car.
You should not drive with a bad thermostat.
Your car may still run for a while and get you where you need to go.
However, it can cause damage to other parts of your vehicle.
You should get your thermostat fixed or replaced before driving your car anymore.
If you feel comfortable working on your car yourself, there are a few things you can check to see what is causing your thermostat to stick.
First, park your car on a flat surface and turn on the emergency brake.
Wait several hours for the engine to cool.
Then, open the hood and find the thermostat using your owner’s manual.
The first thing to check is whether fluid is flowing through the radiator.
Remove the radiator cap (again, first ensure that your engine has cooled completely) and take a step back while still looking at the radiator.
Have someone else turn your car on for you so you can see if fluid is running between the radiator and engine.
Also, check the temperature gauge inside the car.
Next, turn the car off, let it cool once more, then disconnect the radiator hoses.
Check them for any blockages.
Blocked hoses could be keeping coolant from flowing.
If there are no blockages in the hoses, check the thermostat valves to see if they can move up and down.
If they don’t, they may need to be jimmied a bit to a position where they can move freely.
If that can’t be done, they likely need to be replaced.
If your hoses and valves aren’t the problem, you likely just need a new thermostat.
It’s possible to replace it yourself, but a mechanic can also do that for you.
How Does The Temperature Control Sensor Work?
Whether your vehicle has an A/C system or a climate control system makes a difference in how the process of cooling down the interior of your car works.
Cars with A/C systems do not have a second thermostat controlling the temperature of the air inside the car.
A/C systems use refrigerant and air compressors to cool the outside air down before it enters your car.
They depend on the temperature of the air outside the car, meaning that having the A/C on full blast will feel different from one day to the next.
There is no sensor monitoring the temperature of the air inside the car, meaning you will need to adjust the A/C knob to achieve your desired temperature.
It also means that if the temperature outside changes quickly (say, if the sun sets or you are driving up a mountain), you will need to manually adjust for that change.
In cars with climate control systems, the temperature control sensor works similarly to the thermostat in the engine, although in a more advanced manner.
Instead of a valve, the sensor is a computer.
As cooled air enters your car through the vents, the sensor detects the temperature of the cabin of your car and sends feedback to the climate control system.
If the temperature in the cabin is rising when it shouldn’t or is cooling too quickly, the system will adjust aspects of the cooling system, such as fan speed.
This sensor allows you to decide the temperature in your vehicle to a precise degree.
Fortunately, unlike the engine thermostat, the temperature control sensor is not vital to the function of your vehicle, meaning if it goes out, you’re free to keep driving.
It may not be a pleasant ride without a working air conditioner, but you will safely get from point A to point B.
How Do I Know If My Car Has A Climate Control Or A/C System?
Newer cars tend to have climate control, while older ones have A/C systems, but this isn’t always true.
Base models of new cars often only have A/C systems.
Climate control is typically an added feature.
To tell whether your car has climate control or A/C, take a look at your temperature controls.
Ventilation systems usually have dials or buttons that are color-coded: red for warmer, blue for colder.
There is no indication of how hot or cold the air actually will be.
This is because ventilation systems depend on the temperature of the air outside.
Ventilation systems cannot cool the air in your car any colder than the ambient temperature outside.
If you have a button that says A/C, your car also has air conditioning.
Air conditioning cools the air coming into the car using refrigerant, but you cannot control exactly how cold the air is.
It still depends on the temperature outside, though less so than a ventilation system does.
If you see numbers that indicate how warm in degrees the temperature in the car is, that’s a climate control system.
The sensors allow the system to change the temperature in the cabin to the exact degree.
You may even see two temperature gauges.
This is dual climate control.
It means that the driver and the passenger can have different air temperatures coming out of the vents on their side of the car.
What Do I Do If My Ventilation System Stops Working?
If no air is coming out of your vents at all, fortunately, it won’t affect the way your car runs.
However, it will make for a very uncomfortable ride.
There are a few parts to check on if you aren’t getting hot or cold air out of your vents.
One possible problem is a dirty cabin air filter.
As your car brings air in from outside, the air passes through a filter to clean it before it enters the cabin of your car.
Over time, the dirt and grime from the outside air can clog up your filter.
This can reduce the functionality of your heating and cooling systems.
It can even be dangerous, as your heating system may not be able to defrost an icy windshield before you drive on a cold day.
In many vehicles, checking the air filter is relatively simple.
Check your owner’s manual for instructions.
Once you’ve removed the glove box, you will be able to locate the air filter.
Check to see if the filter appears to be overly dirty.
If so, you can use a vacuum hose to clean out some of the grime.
It is not a permanent fix, but it should help increase airflow in your car.
Experts recommend replacing your filter every 15,000 to 30,000 miles.
Another potential issue is a damaged blower motor.
This is especially true if your air filter was completely clogged.
The blower motor pushes the heated or cooled air through the vents in your car.
If your air filter was very dirty and you cleaned it but still aren’t getting any airflow, your blower motor is likely dirty or damaged.
Checking your blower motor requires disconnecting your car battery and removing the blower motor to clear out any debris.
A mechanic can also perform this task for you.
What If My Vents Will Only Blow Hot Air?
If airflow isn’t the issue, but air conditioning is, there are three likely reasons.
The first is that your air conditioner needs to be recharged.
Recharging your air conditioner involves adding more refrigerant to the system.
As your A/C runs, it recycles the refrigerant that runs through the hoses and cools the air.
The A/C system will naturally lose refrigerant over time, but not quickly.
You should not need to recharge your air conditioner every year.
If this problem happens frequently, you may have a leak in your A/C system.
A refrigerant leak can be hard to identify because refrigerant evaporates when it comes into contact with air.
However, there are a few signs to watch out for.
If you hear a click when you turn on your A/C, it could indicate a leak.
You may also hear a hissing noise after you turn your car off.
Finally, if your air conditioning system cycles on and off frequently, you should get it checked.
A professional mechanic can determine if your refrigerant is actually leaking.
The last issue that might be preventing your car from blowing cold air through the vents is a failure with the condenser.
The condenser takes humid air from your car’s air compressor and cools it.
This cooled air is the air that comes out of your vents.
If your air conditioner isn’t cooling your car down the way it’s supposed to, your condenser could be starting to go bad.