When to Replace the Coolant Temperature Sensor in Your Volkswagen

Volkswagens can develop issues with the coolant temperature sensor, which is an extremely important part found within the vehicle’s engine system. These popular German automobiles are known for providing drivers and other occupants with comfortable interiors and luxury features without the massive price tag of a luxury car. Proper maintenance is key. Many Volkswagen owners find themselves wondering when is the right time to replace the coolant temperature sensor.

What is the responsibility of the engine coolant?

Engine coolant, also known as antifreeze, is responsible for continually flowing through the engine system to keep the engine and radiator at optimal operating temperatures. This fluid is mixed with water within the radiator, where it works diligently to keep the moving parts from overheating as well as protecting it from extreme weather conditions.

When coolant becomes too low, it is unable to maintain temperatures needed to allow the engine to function resulting in:

a decrease in fuel economy
the temperature gauge on the dashboard rising
a sweet smell

What is the coolant temperature sensor?

While the coolant is responsible for keeping various parts of the engine system cool, the coolant temperature sensor is responsible for keeping the coolant itself from reaching extreme temperatures.

The coolant temperature system is often attached to the cylinder head or to the engine block itself where it is slightly submerged in the coolant to continually monitor the temperature. Many modern vehicles have at least one coolant temperature sensor, sometimes more.

As the temperature sensor monitors the temperature of the coolant flowing through the radiator and other various engine components, data is sent to the engine’s computer system where it is able to send a signal through the vehicle’s onboard diagnostic system if the antifreeze becomes too hot or too cold.

Common Signs of a Coolant Temperature Sensor Failure

The coolant temperature sensor plays a vital role in keeping the engine running at a comfortable temperature for optimal engine performance. When this part begins to fail, Volkswagen drivers can expect to have the following common warning signs happen:

Engine overheating: When the coolant temperature sensor fails, the temperature of the coolant itself cannot be properly monitored leaving it subject to overheating. When this critical fluid overheats, the engine is left to overheat as well.
A poorly running engine: When the sensor fails, your engine is no longer able to function efficiently resulting in a decrease in power, a decrease in fuel economy, or even backfiring.
Engine stalling: Your engine requires a specific air/fuel ratio to allow for proper combustion to keep the engine running, when any sensors fail that affect the function of the engine, the engine may begin stalling.
Increased emissions: As the coolant temperature sensor fails, your engine will not get accurate temperature readings. When the engine is cold, it requires more fuel for proper combustion. However, when the engine has too much fuel the excess fuel is burned leading to an increase in harmful emissions.
Black smoke: An excess amount of fuel during combustion inevitably leads to the fuel being burned within the exhaust resulting in black smoke coming from the exhaust system.
An illuminated check engine light: Whenever the electronic computer module of your Volkswagen detects a problem of any kind, it sends a signal to the driver in the form of an illuminated warning light on the dashboard. When the coolant temperature sensor fails, the check engine light will become illuminated on the dashboard.

Give Our Experts at Hayes European a Call!

Hayes European was founded in 2004 by John Hayes, who is an automotive expert with more than 40 years of experience. Hayes European provides new-school technology with old-school, quality service. Located in Santa Cruz, California, we help drivers in the surrounding areas, including Aptos, Soquel, and Capitola.

We strive to provide unmatched customer service and dealership-quality service with much lower wait times and costs to you. In an effort to show our excellence in service, we provide a complimentary shuttle service to customers within a 10-mile radius so your service or repairs do not interrupt your day.

We specialize in the maintenance of popular brands including Audi, BMW, Mercedes, Porsche, Sprinter, Volkswagen, and Volvo. Call us today. We look forward to helping you!