Skip the auto shop - Our mechanics make house calls

How Long Does a Coolant Level Sensor Last?

coolant level sensor

The coolant level sensor uses a moveable float device and a reed switch that senses when the radiator has low coolant. Once the sensor detects low coolant, the driver is alerted by a light illuminated on the dashboard. The coolant level sensor is located on the radiator or at the bottom of the expansion tank, depending on the make and model of your vehicle.

The coolant level sensor works with a float that contains a ring magnet. The ring magnet closes the reed switch inside when there is enough coolant in the radiator. Once the coolant drops to a certain level, the float follows the level, the reed switch is removed from the magnet, and contracts the reed switch open. This is when the Coolant light should illuminate on your dashboard.

When the coolant tank is filled to the correct level and the warning light is still illuminated on your dashboard, this may be an indication the coolant level sensor is going bad. If this happens, have a professional mechanic look at the vehicle to properly diagnose the problem. The coolant level sensor can be replaced if it is found to be the problem during inspection.

The magnet switch may fall off over time, the float may get stuck, or the wiring for the sensor may be shorted out. These are all things that can contribute to the sensor going bad. It is important to know when you need coolant in your vehicle, so if you let this problem go, you vehicle could start overheating because your coolant light is constantly on.

Since the coolant level sensor can go bad over time, it is important that you can recognize the symptoms that indicate the sensor needs to be replaced.

Signs the coolant level sensor needs to be replaced include:

  • Coolant light is on but the reservoir tank is full
  • The coolant level is low but there are no warning lights on your dashboard

The coolant level sensor is an important piece to making sure the overall function of your engine is running smoothly. Without the right amount of coolant, the vehicle may overheat and cause damage to the engine so this problem should be taken care of right away.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...

Related questions

Q: My car has check engine light on because of an oxygen sensor

Hi there. Your car has two oxygen sensors. Sensor one is located attached to the exhaust manifold, and sensor two is attached behind the catalytic converter. The one you are getting is behind the converter in the exhaust pipe....

Q: Low Coolant light flashing.

When you see a flashing Low Coolant light on your Saturn’s dashboard, the coolant level sensor is reading that there is no coolant in your expansion tank. This is very easy to verify, just be sure your car is cold,...

Q: Starting problems

Hi, there is a recall on these cars about the TIPM, or Totally Integrated Power Module. If the camshaft position codes have disappeared I would take a look at the TIPM. If the codes are still present, then there may...