4 Signs Your Car Thermostat May Need Replacement - White's Automotive Center (2024)

The thermostat of your car works with the radiator and coolant to help keep your engine at an optimal temperature. When the thermostat is working properly, it works as part of the radiator system flow. The thermostat allows hot coolant to enter the radiator to prevent the engine from overheating. So if you’re experiencing overheating issues, your thermostat may be to blame. Here are four signs that it may need to be replaced.

1. High Temperature

One of the first signs that your thermostat may need replacement is how high the temperature inside gets. It isn’t unheard of for a car to reach a high temperature and possibly become overheated. If you have the car serviced, or if you refill your coolant on your own, this usually helps or fixes the overheating issue. The problem is when the temperature crawls back up quickly and stays high regardless of what you do.

Though high temperatures may indicate a small leak in the coolant tank, they can also be a sign that the thermostat is not working properly. One way to make sure the issue is with the thermostat is to look for quick spikes in the temperature. For example, if you start the car and the engine temperature is cool but spikes very high within a few short minutes, then it may be the thermostat.

2. Cold Engine

There is a misconception that if your car thermostat has gone bad, then your engine is constantly running hot. Though a hot engine is one of the signs that something may be wrong, your engine could also start running cold. A cold engine is also caused by a bad thermostat and can affect the operation of your car.

Keep in mind that the main function of the thermostat is to allow hot coolant to move through to the radiator. The thermostat helps the coolant cool down so the engine will not overheat. If the thermostat remains open, however, the coolant will continually move through regardless of whether it is hot or not. This will cause a cold engine, which can cause mechanical issues with the car.

3. Temperature Gauge Issues

You can easily access the thermostat to check the temperature gauge yourself, which can be the quickest way to decide whether or not your thermostat needs to be replaced. You will need a set of needle-nose pliers to remove the thermostat.

Once you remove it, clean the thermostat off and place it in a bowl of hot water, but make sure you check the temperature of the hot water before placing the thermostat inside the bowl. Place the thermostat into the water and watch the temperature gauge. If the thermostat gauge doesn’t go up, spikes, or goes up far beyond the actual temperature of the water, then your thermostat likely needs to be replaced.

4. Coolant Level Issues

If you start noticing issues with the thermostat check the coolant levels. When you put the coolant into the coolant tank, note where the level of the coolant falls. There should be a fill line on the side of the coolant tank or some way for you to measure the levels. Take note when you refill the coolant and what level it is at after the refill.

If the coolant levels drastically change, then your thermostat may not be working properly. You should see a gradual decrease. If the tank is completely empty, then you could have a leak and a thermostat issue. If you see no change at all, your thermostat may be stuck in a closed position.

If you think your car’s thermostat isn’t working properly, visit us at White’s Automotive Center. We can run a full diagnostic to determine where the issues are with your car and what needs to be repaired or replaced, including the thermostat.

4 Signs Your Car Thermostat May Need Replacement - White's Automotive Center (2024)

FAQs

4 Signs Your Car Thermostat May Need Replacement - White's Automotive Center? ›

Temperature Fluctuations: One of the most common signs of a bad thermostat is erratic temperature readings on your dashboard gauge. If you notice that the temperature gauge moves from normal to hot quickly or fluctuates unexpectedly, it's a clear indication that your thermostat may be malfunctioning.

How to tell if a car thermostat needs replacing? ›

Temperature Fluctuations: One of the most common signs of a bad thermostat is erratic temperature readings on your dashboard gauge. If you notice that the temperature gauge moves from normal to hot quickly or fluctuates unexpectedly, it's a clear indication that your thermostat may be malfunctioning.

What is the symptoms of a bad or failing thermostat? ›

What Are the Signs of a Bad or Broken Thermostat?
  • The AC or Furnace Won't Come On. ...
  • The HVAC System Won't Turn Off. ...
  • The Thermostat Is Unresponsive. ...
  • The HVAC System Short-Cycles. ...
  • The Room Temperature Doesn't Match the Thermostat Setting. ...
  • The Programmed Settings Reset Themselves. ...
  • Check and Adjust the Settings.

What is the life expectancy of a car thermostat? ›

A car thermostat is designed to last a long time – typically around 100,000 miles or 10 years. However, various factors can impact its lifespan. First, driving conditions play a role. If you regularly drive in hot weather or stop-and-go traffic, your thermostat may suffer additional stress.

Can you drive a car with a bad thermostat? ›

If you drive with a bad thermostat, your car could overheat, causing severe and expensive engine damage. And while it's technically possible to drive without a thermostat, we don't recommend it. Your car will not reach an acceptable operating temperature, resulting in higher fuel consumption and excessive engine wear.

How can I tell if I need to replace my thermostat? ›

If you make changes at the thermostat and get no response whatsoever from your furnace, air conditioner, or heat pump, it could mean the thermostat is bad. Thermostat doesn't respond to changed settings: When you make temperature settings at your thermostat, it should almost immediately respond to those changes.

How can I test if my thermostat is bad? ›

The following are six signs that your thermostat is damaged or broken.
  1. Your HVAC System Won't Turn on. ...
  2. Your Air Conditioner or Heater Runs Non-Stop. ...
  3. Differing Temperature Readings Throughout the Home. ...
  4. Short-Cycling. ...
  5. Programmed Settings Keep Getting Deleted. ...
  6. There's No Response to Changes in Temperature Settings.
Jul 19, 2021

How many hours does it take to replace a thermostat in a car? ›

How long does a car thermostat replacement take? An average thermostat replacement takes around 1 hour, with some taking as little as 30 minutes. More problematic replacements can take a little longer where there are issues accessing an awkwardly positioned part or if it's become seriously stuck in place.

What does it cost to replace a thermostat in a car? ›

Car thermostat replacement time is 30 to 60 minutes, depending on the make of the car. It will cost you around $190 to $350, including labor. Thermostat repairs usually take more time, requiring extra time to diagnose and analyze the vehicle's thermostat. It can take up to 2 hours.

What causes a car thermostat to go bad? ›

There can be many reasons that cause a failing car thermostat, including a bad water pump, loose water pump belt, leakage in the cooling system, collapsed radiator hose, and the clogged and failed radiator.

Will a bad thermostat throw a code? ›

While there is a small chance that there is an issue with the running temperature of your engine, by far the most common issue with trouble code P0128 is a faulty thermostat. The exact location of the thermostat and issues related to a damaged thermostat may vary depending on your vehicle.

How much does a new thermostat cost? ›

Cost Estimator by Thermostat Type
Thermostat TypeAverage Cost (Thermostat Only)Average Cost (Including Professional Installation)
Manual Thermostat$20 – $40$40 – $150
Digital Thermostat$40 – $150$60 – $350
Wi-Fi Thermostat$60 – $230$120 – $400
Smart Thermostat$140 – $310$150 – $500
Nov 30, 2023

How do you test a car thermostat? ›

Place the thermostat in a pot of water on the stove. Turn on the heat and use a thermometer to monitor the water temperature. As the water heats up, observe the thermostat. It should start to open around the specified temperature (usually marked on the thermostat).

How often does a thermostat need to be replaced in a car? ›

However, most car experts recommend car thermostat replacement after 10 years. However, this is an optimistic number. Thermostats are more likely to stop working much earlier than a decade. Some factors that induce an early thermostat failure include harsh weather, rough driving, bad engine or thermostat parts.

Does changing car thermostat make a difference? ›

The benefits are clear: more precise temperature regulation and improved engine performance to enhance fuel efficiency and protection against engine wear.

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