Bad Coolant Level Sensor Symptoms

What Is the Coolant Level Sensor?

The coolant level sensor , also called the coolant level indicator, reports low radiator coolant, which is an important piece of information for the person driving the vehicle. Coolant level sensors vary in design and operation, but they all have the same job to do.

Coolant level sensors are either in the plastic coolant reservoir/surge tank or are in the radiator itself. Some GM coolant level sensors beginning in the 1990s don’t contain a switch but have a single gold plated stud supplied with a reference voltage and can detect coolant concentration as well as coolant level.

Other GM cars might have a sensor with a plastic float that has metal contacts on the bottom side to close a circuit when the coolant level gets low. Usually, the signal is sent to a module or the BCM and a request is sent to the instrument cluster to turn on the low coolant light or display the message.
The coolant level sensor is generatlly made to last the life of the vehicle, but they sometimes fail. It can also get damaged during an accident. While a bad sensor won’t cause major issues, it can’t warn you about the engine potentially running low on coolant fluid. Therefore, you should replace it as soon as possible.

Bad Coolant Level Sensor Symptoms

Ignoring a problematic coolant level sensor might lead to more serious engine issues that will cost more to repair. To save both time and money, replace a bad sensor as early as possible.

Keep an eye out for the following warning signs:

Warning light stays on

Some vehicles will have a coolant light on their dashboard. This light will illuminate when the coolant level sensor detects a dangerously low coolant level. In other vehicles that don’t have a dedicated coolant light, the sensor will turn on the check engine light to warn you about the low coolant level.

A faulty coolant level sensor can trigger the warning light and keep it on, even if the engine has enough coolant fluid. You might refill the coolant reservoir prematurely, leading it to overflow. If you ignore the perpetually lit coolant light, you might not notice when your vehicle is low on fluid. A constantly running warning light might also overheat and burn itself out if it runs for too long.

Low coolant level doesn’t trigger the sensor

A fully functioning coolant level sensor will activate the warning light the moment it detects that the coolant fluid has become critically low. However, if the sensor was damaged or worn out, it might not be able to correctly measure the amount of coolant in the cooling system.

A faulty coolant level sensor won’t be able to detect low coolant levels, nor will it activate the coolant light or check engine light.

Engine overheats despite normal coolant level readings

A bad coolant level sensor won’t directly cause the engine to overheat. However, it can prevent you from realizing that the coolant fluid has gotten depleted to the point that it can no longer keep the engine cool.

Without sufficient coolant fluid, the engine will run hotter than normal. This will put greater strain on various parts, reducing their overall lifespan. Engine components like the cylinder head, gaskets, and exhaust valves can even get damaged, which can lead to severe consequences for the engine and the rest of your vehicle.

Keep in mind that a bad coolant level sensor isn’t the only possible reason behind an overheating engine. If you want to fix your vehicle yourself, make sure to check other engine parts thoroughly to make sure that the sensor is that malfunctioning part.

More About the Coolant Indicator Sensor

In most vehicles, the coolant level sensor is found in the coolant reservoir, coolant overflow bottle or expansion tank, or the radiator. Radiator-mounted sensors are often installed inside the cooling device if the vehicle was manufactured before 2010. Newer models have externally mounted sensors attached to the side of the radiator, making the sensor easier to access. If you can’t find the coolant indicator sensor in these parts, consult your vehicle’s owner’s manual.

The coolant level sensor shouldn’t be mistaken for the coolant temperature sensor. This sensor measures coolant temperature, not the amount of fluid that can cool the engine. However, both sensors contribute critical information about the engine’s current operating temperature.

What Does a Coolant Level Sensor Do?

No matter its location, the coolant level indicator also measures the amount of fluid in the engine’s cooling system. It has metal terminals that react to magnetism.

The coolant level indicator doesn’t work alone. It relies on a magnetic float inside the coolant reservoir, coolant overflow bottle, or radiator. The float rises and drops along with the coolant level.

When the coolant level drops past a certain point, the coolant level sensor will transmit a warning signal to the powertrain control module (PCM). The PCM turns on the dashboard warning light to let you know that the engine’s coolant level is dangerously low.

In some vehicles, the PCM might also put your vehicle in safe mode to lessen the production of heat.

If the coolant drops to a dangerously low level, the coolant level indicator will activate the appropriate warning light. If you see the coolant light or check engine light turn on, you should check the engine’s coolant level immediately. If the coolant has reached a critically low level, you’ll need to add new fluid.

DIY Replacement of a Bad Coolant Level Sensor

You can replace a faulty coolant level indicator if you have the right tools and sufficient DIY auto repair knowledge. You might have to remove some engine parts to access the sensor, depending on its location.

If you lack automotive know-how, bring your vehicle to a trusted service center and ask a  professional mechanic to examine the coolant level sensor.

How Much Does a Replacement Coolant Level Sensor Cost?

A replacement coolant level sensor can cost anywhere between $10 and $235. The price can vary based on the pump’s brand and your vehicle’s year, make, and model.

Where to Get a New Coolant Level Sensor for Your Vehicle

Driving around with a damaged coolant level sensor might not seem like a major problem一until you see smoke coming out of your hood because of its inaccurate readings. So when it’s time to shop for a top-notch coolant level sensor replacement, make sure to get one from CarParts.com.

As a leading retailer of aftermarket car parts, we make sure to offer drivers like you only the best replacement parts for your ride. All our coolant level sensors are manufactured with OE-grade materials and passed strict quality checks from the leading names in the industry. What’s more, you can enjoy these benefits without having to break the bank because our products come with a low-price guarantee.

All it takes is a few clicks to get started. Simply enter your vehicle’s year, make, and model into our vehicle selector to narrow down the search results to all compatible coolant level sensor replacements for your ride. Place your order in a matter of a few minutes, and get it delivered straight to your doorstep in as fast as two business days.

Grab the best deals on a coolant level sensor today here at CarParts.com!