A comprehensive guide: How to tell if thermostat is bad in car?

Do you drive regularly? If you do, you’d know the thermostat is an integral car component. The main purpose of the thermostat is to get the engine heated and maintain an ideal temperature. It has a little chamber, which contains a wax capsule that softens and expands at a particular temperature. Next, it makes use of a stick to open a valve that lets the antifreeze flow to the radiator.

However, there may come a time when the thermostat stops performing. Now, how to tell if thermostat is bad in car?

There are myriad ways to assess the functioning of your car’s thermostat, but your course of action will depend on what signs your car displays. Before getting into the details of bad thermostats, it is imperative to understand the dynamics of a car thermostat.

symptoms-of-a-bad-thermostat-in-car
Source: autovfix

A car’s thermostat- what does it do?

To work effectively, vehicles with a particular water-cooled engine must operate at a temperature between 195 and 220F. For this purpose, the car thermostat functions as a controlling device; it allows the fluid to enter the radiator in high temperatures and holds it back in case of low temperatures. Simply put, the objective of the car thermostat is to keep the temperature in the ideal range, thus ensuring top performance.

How to tell If  thermostat is bad in car?

Since a thermostat is a core car part, it needs to be operating efficiently at all times. If the thermostat is failing, it would hinder the smooth operation of the car and ultimately hinder its smooth functioning in the long run. Hence, if your car engine shows any signs of malfunctioning, you must check and rectify the problem in the car’s thermostat immediately.

One of the most common issues that disrupt the smooth functioning of the engine is the thermostat’s position. For instance, if a CT happens to be open, the temperature of the engine will fall below the optimum level. The situation may get worse if you are driving on the freeway in frosty weather. On the contrary, if the car’s thermostat is closed, your engine is most likely to overheat. If the car’s thermostat isn’t fixed, your engine will debilitate sooner or later.

symptoms-of-bad-car-thermostat
Source: cartreatments

If you find yourself stuck in such a situation, you don’t have to fret as you can fix the thermostat of your car yourself. Here’s how:

Park your car on a flat surface and turn on your emergency brakes. Wait for a few minutes till the machine has cooled, open the hood of the car, and assess the liquid level.

Next, locate your car’s thermostat, open up the top part of the radiator and ask someone to start your vehicle. As soon as the vehicle starts, observe to see the fluid entering the motor. After careful examination, stop your vehicle and assess the thermostat’s piping. (The top pipes must be less hot as compared to the lower ones.)

Extract the tubes and note signs of a blockage- If they remain fixed in their position and can’t move, the problem has been located. All you need to do is change the valves now.

But, if the tubing is working fine, then change the thermostat

If you’re still and don’t know how to tell if thermostat is bad in car, here is a comprehensive list of symptoms that your vehicle may show:

coolant-leak
Source: cartreatments

Shifting problems

If you experience a shifting problem while driving, it is probably because of the fluid that was contaminated by cool fluid and if it remains unfixed, it would damage the whole system.

Heater problems

If the car’s heater isn’t working, the radiator has likely caused such a problem to occur. The heater is dependent on the coolant and its inability to function may be due to the radiator being clogged.

Engine malfunctioning

The simplest way to know about a car’s thermostat performance is to just observe the overall performance of your car. If the thermostat is not functioning at its full capacity, your car’s performance will be disturbed. Thus, if this problem isn’t fixed at the earliest, it would result in lower gasoline mileage and many other issues that may leave a dent in your wallet.

check-engine-light
Source: cartreatments

Incessant Temperature Fluctuations

If your vehicle keeps changing temperatures, it is most likely because of a faulty car thermostat. These rapid fluctuations are caused by the movement of the thermostat, which means that the cooling fluid isn’t flowing normally.

Do it yourself: how to tell if thermostat is bad in car

You don’t always need a mechanic to fix your vehicle. If you think your car thermostat isn’t functioning to the optimum level, you can try seeing it for yourself. All you need are nose pliers, gloves, and patience to start the process.

First off, wear your gloves and extract the car thermostat so a better assessment could be made. If it’s closed, there is no reason to worry, but if it’s open, you’ll have to purchase a new CT. Next, put a container on a stove and empty water, just enough to fill the thermostat. Right when submerging, be careful to stop it from going to the base of the container. (Tip: nose pliers can be of great help.)

A Car’s Thermostat
Source: cartreatments

Start with boiling water and record the temperature. Just when the car thermostat begins to widen, note the temperature. You shouldn’t extract it from the water until and unless the thermostat is open completely. Later, when it is open to the full extent, extract it from the container and compare it to the details mentioned on your vehicle. If results seem to vary from the specifics of the vehicle, your thermostat needs to be replaced.

How to replace a thermostat in car

If your thermostat is completely out of order, it has to be replaced right away. Here is an overview of the steps you’d need to undertake:

Park the car on a flat surface. Next, use a screwdriver to remove the locks that fasten the radiator together. The bolts on the thermostat also have to be loosened with a wrench. As soon as you open the top part, the thermostat will be out as well.

Remove the dirt present in the system. Then, all you need to do is buy a brand-new car thermostat, use bolts to secure it in place, and put the radiator hose and clamps back together.

Lastly, wait for the car to reach the optimum level of heat. You can then take it out to test your new car thermostat.

We hope this article helps you answer all your questions on how to tell if thermostat is bad in car. If you have a bad thermostat that needs to be replaced and doesn’t get enough time or energy to do it yourself, you can always seek professional assistance to get the work done.

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