This is an easy problem to solve yourself by simply removing the plastic outer casing and, with a very soft brush, delicately brushing off its coil and contact surfaces. It is most effective to clean the thermostat first at its lowest setting, then again at its highest setting.
A thermostat may periodically stick due to wear or damage, debris or sludge buildup, incorrect or low coolant, or faulty temperature sensors or wiring. These issues can cause inconsistent engine temperature regulation.
Why Won't My Thermostat Let Me Change the Temperature Setting? Locked unit: Check if the child lock setting is activated. You'll need to disable it before you can change the temperature. No power: If the thermostat isn't working at all, there could be a power issue.
Driving with a thermostat stuck closed can lead to serious engine problems. The thermostat regulates the flow of coolant in the engine, helping to maintain an optimal operating temperature. If it is stuck closed, the coolant cannot circulate properly, which can cause the engine to overheat.
Generally, repairing a thermostat costs around $200 to $500. This is the price range you'll find for most vehicles, although some may be higher or lower depending on the circumstances. But if we're talking complete replacement, expect the price to increase by $50.
You can try to clean or knock on a thermostat to get it unstuck. However, that's only a short-term fix you should not rely on. Remember: a stuck thermostat is terrible news for your engine, regardless of whether it's stuck open or closed. So, the best thing you can do is replace your stuck thermostat with a new one.
If stuck open, the thermostat will allow coolant to continue to flow into the engine, even when it doesn't require more coolant. If this happens, and you turn the heater on simultaneously, then only cool air will come out of the vents, no matter how high you turn up the heat.
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.
The average cost for car thermostat replacement is $661 to $747. Enter your vehicle's information to see how much thermostat replacement costs in your local area.
Thermostat is stuck on one temperature
If your thermostat is stuck, the first thing you should do is make sure your system isn't locked. Bumping into your thermostat or accidentally pressing the wrong button can result in it becoming locked, but unlocking it is a quick process.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
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.
Some of the most common thermostat issues include:
The thermostat is broken, not properly level, or dusty. The thermostat needs to be recalibrated. There is loose wiring causing a thermostat issue.
If the thermostat opens too late (at too high of a temperature), or sticks closed, the engine will get too hot. This can cause overheating and damage to the engine itself.
This is an easy problem to solve yourself by simply removing the plastic outer casing and, with a very soft brush, delicately brushing off its coil and contact surfaces. It is most effective to clean the thermostat first at its lowest setting, then again at its highest setting.
Can people drive a car with the thermostat not working? If a water-cooled engine thermostat gets stuck open, then the car may be drivable, but it may eventually foul itself because it will not reach operating temperature where fuel metering and burning are calculated to be efficient and not wasteful.
Thermostat Replacement: If the thermostat is indeed the culprit, it's time to replace it. Locate the thermostat housing (usually near the engine block), drain some coolant, remove the housing, and carefully replace the thermostat.
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.
Although it may be possible to drive short distances with code P0128 set, you should get the issue fixed by a professional right away. Doing so will help ensure your vehicle keeps running at its best while also helping to prevent any additional damage.
Overheating is the most common symptom of a failing thermostat. Due to corrosion or aging, your car's thermostat can get stuck in a closed position. If this happens, the thermostat will not let the coolant reach the radiator, and, as mentioned above, the engine will overheat, causing severe damage.
Thermostats can malfunction or break but this is typically unusual. Many issues can be fixed with DIY thermostat repair. We'll detail some tasks you can do before thinking about hiring a professional.