Thermostat Buyer’s Guide
- A vehicle thermostat is a component that helps the engine stay within the right temperature range for optimum performance.
- The thermostat is responsible for regulating the delivery of coolant from the engine to the radiator. It works as a gate valve that permits or blocks the flow of coolant to keep engine temperatures between 195°F and 220°F.
- This device is never fully open or closed while the vehicle is operational. Thermostats have a ‘rated’ temperature that determines when the valve will start to open. This temperature allows the wax inside a small cylinder in the device to melt and expand, pushing the connecting rod out of the cylinder and opening the valve.
- The cost of an automotive thermostat will vary depending on your vehicle’s specific year, make, and model. OE replacement parts will typically cost you anywhere between $3 to $600. They are sold individually or as part of a kit.
- The signs of a bad or failing thermostat includes engine overheating, engine underheating, erratic temperature gauge readings, and engine coolant leaks.
- The temperatures in your engine are as important as the temperatures inside the passenger cabin. Keeping your vehicle’s engine at the right temperature ensures that it performs at the optimum level and allows you to prolong its life span.
- It is not safe to drive a vehicle with a diagnosed thermostat problem. Failing to repair or replace this component can result in significant and costly damage to your engine.
- It’s a good rule of thumb to replace the thermostat any time you do any major repairs or parts replacement in your car’s cooling system. You should also replace this component after your engine overheats
What is a thermostat?
A vehicle thermostat is a component that helps the engine stay within the temperature range for optimum performance. It is located between the radiator and engine of a liquid-cooled car. The thermostat is a critical part of your vehicle’s cooling system.
How does a car thermostat work?
The thermostat is responsible for regulating the delivery of coolant from the engine to the radiator. It works as a gate valve that permits or blocks the flow of coolant to keep engine temperatures between 195°F and 220°F.
Thermostats have a ‘rated’ temperature that determines when the valve will start to open. This temperature allows the wax inside a small cylinder in the device to melt and expand, pushing the connecting rod out of the cylinder and opening the valve.
As the engine warms up, the opened thermostat valve allows coolant to be circulated through the engine to pick up excess heat. Once the engine heats up to the right temperature, the hot coolant is delivered to the radiator where it is cooled off before it is sent back to the engine. The thermostat’s role is to keep the coolant from flowing back to the engine before optimum working temperatures are reached.
This device is never fully open or closed while the vehicle is operational. If the thermostat breaks and coolant is recirculated before the engine has had a chance to warm up, it will take longer and require more fuel to get the performance you want out of your vehicle.
Signs that you need to replace a bad or failing thermostat
A properly functioning thermostat is critical to the operation of your vehicle’s cooling system. Consult a trusted mechanic as soon as you notice one or more of the following symptoms of a malfunctioning thermostat.
A thermostat stuck closed is a common cause of engine overheating. Temperatures in the engine can spike up minutes after starting your vehicle since the hot coolant has no way of reaching the radiator to cool off.
A thermostat that is stuck in the open position will have engine coolant flowing non-stop towards the radiator—even before it has warmed up to the optimum temperature to function properly. This can lead to faster wear on engine parts and increased vehicle emissions.
Erratic temperature gauge readings
If your temperature gauge reads too high or low, this could be a sign of a failing thermostat. When this happens, the valve controlling the coolant is most likely opening or closing when it is not supposed to. Fluctuating temperatures and incorrect readings will lead to poor engine performance. Have a licensed mechanic check your vehicle to prevent costly repairs down the road.
Engine coolant leaks
Identifying a coolant leak can be tricky, especially for people who are not familiar with the engine cooling system. Most vehicle owners notice an engine coolant leak thanks to the low coolant warning light.
You can also check your garage or parking spot for a red, green, or blue puddle underneath your vehicle. Keep in mind that engine coolant is highly flammable and may become a fire risk. To properly diagnose and fix a coolant leak, consulting a professional mechanic is highly recommended for your safety.
Why is car thermostat replacement important?
The temperatures in your engine are as important as the temperatures inside the passenger cabin. Keeping your vehicle’s engine at the right temperature ensures that it performs at the optimum level and allows you to prolong its life span.
It is not safe to drive a vehicle with a diagnosed thermostat problem. Failing to repair or replace this component can result in significant and costly damage to your engine.
It’s a good rule of thumb to replace the thermostat any time you do any major repairs or parts replacement in your car’s cooling system. You should also replace this component after your engine overheats—regardless of whether the thermostat was the main cause of overheating.
Use our website’s search feature to find the right thermostat for your vehicle. Simply plug in your vehicle’s correct year, make, and model to browse through our vast collection of compatible parts.
Choosing the right thermostat for your car
A thermostat is a simple device inside your car's engine that functions just like a thermometer. It measures the variations of temperature around the engine. These temperatures matter a lot because they tell when the cooling system of the car needs to be activated. It also allows water to flow in the engine to keep it running and to prevent the car from overheating.
There are other things about the thermostat that you may want to know in case you're planning to buy and replace the old one. Here are the functions, types, and features of a thermostat.
The fundamental function of a thermostat is to regulate the temperature around the engine. It tells when the temperature is too high or too low. If the engine is too hot, the thermostat would then allow the coolant to flow to the radiator. It also works the other way around. When you're warming the car up in the morning and the engine is still a bit cold, the thermostat does not allow water to run to the radiator so that you can heat up the engine to its optimum.
The thermostat is made up of the body or the frame, the valve, and a ball of wax. The body is made of a high-quality compound that can resist rust and extreme heat and moisture. The ball of wax is right at the middle of the valve or the opening. When the engine runs and reaches a certain high temperature, the ball of wax starts to melt and opens the valve to let the water flow and cools the engine down.
Tips for Buyers
Sizes of thermostats vary so always check the original before buying a replacement. Always compare the new one with the old. You can check your car's manual to see if it states a particular type or brand of thermostat to be put on your vehicle.
When it comes to type, the only difference is the pre-set temperature in which the valve should open. Car models at present usually have 190 to 195 degree-Fahrenheit threshold. There is no standard type though. You should also take into consideration the kind of vehicle that you have. If you have race cars or sports cars, better use a 160 degree-Fahrenheit type so the engine won't overheat quickly.
Some people think that thermostats are not important. This is a common misconception. Without the thermostat, it will take longer for the engine to reach the normal operating temperature. There will be more fuel usage and more gas emissions. So don't be fooled by this disbelief.
How much is a replacement car thermostat?
The cost of an automotive thermostat will vary depending on your vehicle’s specific year, make, and model. OE replacement parts will typically cost you anywhere between $3 to $600. They are sold individually or as part of a kit.
HJow long does it take to change a car thermostat?
If you have enough DIY auto repair experience and the right tools, it should take you around 30 minutes to replace a car thermostat. For your safety, don't attempt the replacement job if you're unsure about your skills. However, if you really want to fix your vehicle yourself, make sure to consult your owner's manual.
How to replace the thermostat on your car
There are two common scenarios that tell that you have to replace your car's thermostat:
1. Thermostat is permanently open
When the thermostat's valve is stuck open, the coolant in your engine keeps on flowing around the radiator all the time. To detect this problem, simply start the engine, remove the radiator cap and look inside the radiator. If you see that the coolant is flowing, most likely the thermostat is fixed to its open position.
2. Thermostat is permanently closed
If the thermostat is stuck close, your engine tends to overheat fast. If this problem persists, it can cause a lot of damage on the engine. If you want to verify if this is the problem that you have, simply start the car and observe the temperature meter. Now, open the hood and feel the radiator hose and the radiator itself. If these parts seem a bit cold, stop the engine. This means that the thermostat is left closed.
If you are experiencing any of these scenarios, you definitely have to act quickly and replace your car's thermostat. Here is a step-by-step procedure that you can follow.
Difficulty Level: Easy
Duration: 30 minutes
Here are the tools that you need:
- Ratchet set
- Flat-blade screwdriver
Step 1:Check your car's manual for the particular thermostat that you should use in accordance to your vehicle's type, year, and model. Purchase the correct thermostat kit at your local auto parts store.
Step 2: Place a rag around the radiator cap before opening it. Do not remove the cap quickly. Turn the cap slowly and listen to the pressure being released from the radiator. When the sound stops, you take away the cap completely.
Step 3: Find the thermostat. It is usually attached to the two-inch thick black hose. Slowly pull it until you see the cover of the thermostat.
Step 4: Remove the hose from the thermostat cover. Be careful of coolant droppings that might dispense from the hose once you pull it out. Use a rag or container to wipe off or catch coolant droppings.
Step 5: Release the thermostat from its cover. There are two bolts that hold the thermostat to the cover. Use the appropriate size of ratchet or socket to remove these bolts.
Step 6: Use a scraper or emery board to take out any residue of the old gasket from the thermostat cover and base. See to it that you remove the entire old gasket because if not, the cover will leak.
Step 7: Get the new thermostat and put it I place. You can see that there's an extra space on top of the thermostat. This is where you spread the gasket sealant. Spread it to the part that touches the engine on the cover base. The bolt holes should also line up so always pay attention to the base.
Step 8: Replace the cover of the thermostat. Screw the bolts tightly.
Step 9: Replace the hose.
Step 10: Before you start the engine, wait for a few minutes to let the sealant dry. Once, it is dry, rev up the engine and let it warm up for a few minutes. Inspect the thermostat cover and hose to see if there are leaks.