Is it okay to drive a car with a stuck thermostat?

Author: Jadon Muller  |  Last update: Tuesday, June 23, 2026

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.

How long can you drive a car with a bad thermostat?

Depends on the mode of failure. If it's stuck open you could still drive indefinitely, the engine would just take longer than normal to warm up. However if it thermostat is stuck closed, I wouldn't try to drive it more than 5–10 min or the point w...

Will a stuck open thermostat cause damage?

no physical damage to the engine from running with a stuck open t'stat...the only thing that will happen is the engine will not run as efficiently if it does not each normal operating temp...but it is such an easy and inexpensive job to replace a t'stat so why not just replace it?...

Can I still drive my car with a P0128 code?

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.

How do 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.

Driving Without a Thermostat. Is it a Good Idea?

Will the p0128 code clear itself?

This is referred to as a permanent code. This permanent code will go away on its own after the monitor runs and passes. Until then it will be present but only when read with a scan tool and will not turn the light on. If the problem Is detected again by the computer it will first set a pending code.

How do you unstick a stuck thermostat?

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.

How does a car act when the thermostat is bad?

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.

How much does it cost to fix a stuck open thermostat?

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.

How urgent is a thermostat replacement?

HOW IMPORTANT IS A THERMOSTAT SERVICE OR REPAIR. It is never good to have an over-heating engine. Delaying replacement of the engine thermostat and continuing to drive the car can only result in far more costly engine repairs or replacement.

How to tell if your thermostat or water pump is bad?

Here are signs you've got a bad pump or thermostat.
  1. Corroded Cooling System Parts. Both of these cooling system parts can get corroded if they start to leak slowly. ...
  2. Leaking Engine Coolant. ...
  3. Erratic Temperature Changes. ...
  4. Poor Coolant Circulation. ...
  5. Overheating Constantly.

What happens if you don't fix the thermostat in your car?

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.

How much does it cost to replace a thermostat?

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.

Why is my thermostat stuck on one temperature?

If this doesn't work, try resetting your thermostat with the reset button, changing the batteries, or cleaning off any dust and dirt inside. If the temperature is still stuck, an electrical or display issue might be to blame. Contact an HVAC professional for further help.

What is the code for a thermostat stuck open?

Causes of a P0128 code include:

A thermostat that's malfunctioning or stuck open (electronically controlled or traditional)

Can I drive with a thermostat stuck closed?

If it's stuck closed, the coolant can't circulate, causing the engine to overheat, which can lead to severe engine damage. Driving with a bad thermostat is like playing Russian roulette with your engine. The longer you drive with a faulty thermostat, the more you risk causing significant damage to your car.

How much is a new thermostat for 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.

Can I drive with a faulty thermostat?

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.

Will a stuck thermostat cause no AC?

So, can a bad thermostat cause your AC not to cool? Absolutely.

How to check if coolant is flowing?

Well check the resivor with the car running if there is a change in fill level when you remove the cap then it is flowing, or keep an eye on the temp dials once the temp starts rising feel the tube that goes from the top of the radiator to the engine, if it feels warm then the coolant is flowing.

Will a stuck thermostat throw a code?

A stuck thermostat will also trigger several indicators, warnings, and fault codes. As you read above, you'll first notice the blue low-temperature indicator that constantly stays on.

What happens if I unplug coolant temperature sensor?

It's not recommended to unplug the coolant temperature sensor unless necessary for diagnostic purposes, as it can adversely affect engine operation and potentially cause damage if left unplugged for an extended period.

How do I know if my engine thermostat is bad?

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.

Previous article
Does mold wipe off walls?
Next article
Should you scatter soap in your yard?