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.
One easy thing you can do to check the accuracy of your thermostat is to do a temperature check. See what your thermostat reads. Then use a portable indoor thermometer to compare the temps. Another good way to do the temperature check is to download one of the many free apps that allow you to check indoor temperatures.
Replacing a Thermostat. You'll pay between $15 and $300 for the unit in addition to labor ($65 to $100 per hour) to replace an old thermostat with a new one. However, installing a brand-new thermostat is more involved and, therefore, more expensive.
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.
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.
High temperature readings
The main symptoms of a failing thermostat are related to engine overheating. It can be easily noticed because the temperature gauge in the vehicle will probably read unusually high. This can be caused by the valves being stuck in a closed position.
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.
If your thermostat has fresh batteries but suddenly lacks power, flashes, or isn't responsive to adjustments, it may need replacement. If resetting the thermostat doesn't resolve the problem, you may have wiring problems or faulty components causing your thermostat to not turn on.
Corrosion occurs, among other things if a wrong coolant is used. The corrosion attacks the thermostats aluminum parts that almost "etch away" (see figures 1 and 2). But also mixing of different coolants can cause corrosion. Therefore avoid mixing different types of coolant together.
You Notice Erratic Temperature Changes
If you notice sudden and erratic temperature changes from cold to hot or hot to cold, then it could be a sign that your thermostat has stopped working correctly. Get your vehicle inspected if you notice these extreme temperature changes in your vehicle interior.
When you set the thermostat above or below the current room temperature, you should hear a click, and the AC or furnace should kick on almost immediately. If you make changes at the thermostat and nothing happens, that's the first sign you have 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.
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.
Installation typically takes about 1 hour.
Luckily, it only takes a few minutes and a couple of tools to change your thermostat yourself. Our guide will show you how to remove the bad thermostat and replace it with a new one!
In most cases, installing a new thermostat is a relatively simple do-it-yourself project that can result in improved comfort and convenience and one that can help you save energy.
If it's broken in a way that the engine is running too hot, don't drive it. Watch the gauge on the instrument panel and see which it is.
If you need to replace your radiator, you can expect to spend between $700 and $1,000. You can save on labor costs (about $300) by replacing the radiator yourself if you're experienced with auto DIY jobs. Keep in mind this is a big undertaking that will likely take all day.