Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Low Water Sensor

water sensor

Bad or Failing Low Water Sensor Inspection

by a top-rated mechanic at your home or office

Low water sensors are more commonly known, or referred to, as coolant level sensors. The purpose of these sensors is to alert the driver of low coolant level in the engine cooling system. When coolant level in the engine is low, the cooling system cannot adequately remove excess heat from the engine. This causes the engine to overheat which will lead to eventual engine failure. The most common results of engine overheating include warped or cracked cylinder heads, and blown head gaskets.

HAVE SYMPTOMS OF CAR TROUBLE?
Get an $80 diagnostic
by a top-rated mechanic at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

Normal operation

The typical coolant level sensor has two probes that, when inserted into engine coolant, pass electricity between them. This creates a complete electrical circuit. When coolant level falls below the probes, the circuit is broken and the low coolant level warning lamp is illuminated. This alerts the driver to have the cooling system checked.

There are basically two symptoms of a failed coolant level sensor.

Low Coolant Warning Light always on

Since the Low Coolant Warning Light is illuminated when the lamp circuit is electrically open, the sensor could go open internally regardless of actual coolant level. This would cause the coolant light to always be on. The necessary repair here would be to replace the sensor.

HAVE SYMPTOMS OF CAR TROUBLE?
Get your car fixed at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

Low Coolant Warning Light does not illuminate on low level

If the coolant level sensor is electrically shorted internally, the coolant level circuit will never go open when coolant level falls too low. This prevents the Coolant Level Warning Light from illuminating and alerting the driver to a potentially hazardous situation. If the cooling system isn’t checked on a regular basis, engine damage may occur.

Have a trained technician like those at YourMechanic diagnose the condition. If the sensor needs replacement, they can do that. If another issue is the cause, they can fix that, too.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

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

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.

GET A QUOTE

More related articles

What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...
P0359 OBD-II Trouble Code: Ignition Coil I Primary/Secondary Circuit Malfunction
P0359 code definition The P0359 code indicates that a fault has been detected in one of the vehicle’s ignition coils, generally the number 9 coil. This code can also be associated...


Related questions

Q: Losing coolant air conditioner and heat not turning on at all

Hey there, thanks for writing in about your 2003 Chrysler Sebring. The problem is that you are low on coolant and the A/C needs to be diagnosed to see why it is not working. If you have a coolant leak,...

Q: When starting, car shakes and rattles and then quits

Sounds like you aren't getting enough fuel during "cold" start. First thing, check the cold start injector, and thermo time sensor, which regulates how long the cold start injector squirts. Next, check the Over-Voltage Protection relay and circuit. If this...

Q: Overheating now hesitates today start 2001 Buick LeSabre

Hi there - I think your cooling system needs careful attention. If the thermostat was replaced, the system may not have been adequately bled, and there is a large air pocket in the engine. This will cause a rapid overheat....