What is a blinker fluid?

This blog will explain different types of fluids in a car and answer the following questions: what is a blinker fluid? Why does water get in the blinkers or other lights? What are the types of fluids in the car that require top-up?

What is a blinker fluid? 

A blinker fluid is a fake product,  it is one of the most popular pranks on social media where people with no knowledge of operating fluids in a car go to spare parts shops or gas stations to buy a blinker fluid. The trend started in 2016 when a video of a father pulling the same prank on his daughter went viral.

After the trend started in 2016, the Blinker fluid prank rose to popularity in the following year. Many fake bottles of blinker fluids containing water started appearing on top online shopping websites. 

One of the famous automotive content creators on Youtube; Chrixfix, even made a video on how to replace a blinker fluid in a car. The video also has over 6 million views. The products used in the video are fake and it is a prank video that is targeted toward people with no knowledge of automotive maintenance.

Turn signals on a car are usually referred to as blinkers. There are filament bulbs or LED lights that work on a 12 V power supply from the vehicle’s battery. Turn signals do not require any fluid to operate; the light from the bulbs becomes more visible as it gets reflected on the mirror surfaces inside.

The blinkers are located on the front as well as on the backside of a vehicle. A hazard switch is also present on all automotive vehicles and the use of a hazards switch was mandated by the US government in 1966.

A hazard switch can actuate all the turn signals in a car, it is used in an emergency situation to warn the drivers behind the car. Some of the premium luxury cars like Mercedes Benz, Audi and BMW even actuate all the turn signals if the vehicle is significantly slowed down under heavy braking.

Why does water get in the blinkers or other lights?

Although blinker fluid is an imaginary liquid, water does get into the tail lamp or headlamp housing. Ideally, the lamp unit in a vehicle is completely sealed off from the environment. There is a cap provided on the back of the lamp housing for replacing the bulb. 

Cap has a rubber seal and the lamp housing has sealant to protect the electrical wiring and control unit from moisture. This sealant can get damaged due to the heat from the bulbs or the maintenance cap can fall off, exposing the insides of the lamp unit to the environment.

When the vehicle with a damaged seal or missing cap goes through an automatic car wash or is driven through heavy rains, water enters the lamp unit. The lamp housing is not designed with a drain so the water continues to saturate the lamp housing.

Another reason behind water in the headlamps or tail lamps is condensation. Condensation is a naturally occurring phenomenon. Water vapours are condensed on the cold surface when there is a temperature difference between the surfaces.

Condensation in the headlights or taillights is very common in cold or rainy weather and usually goes away when the temperature difference is not present. However, if the vehicle is not used for many days then due to excessive condensation water droplets begin to form in the lamp housing.

Water in the lamp or blinker can severely damage the electrical wiring or control units present in the housing. Therefore water must be removed as early as possible, one of the ways is to remove the lights and drain the water from the maintenance cap.

After the water is completely drained, allow the lamp unit to dry in sun or use a heat gun to remove the remaining moisture. Inspect the lamp housing for any damage or crack, and replace the lamp unit if the leak cannot be repaired.

If water is present in the lamp unit due to condensation, there are various methods to rectify it. The easiest method is to simply turn on the lights for 10-15 minutes and allow the condensation to disappear. Another method is to use a desiccant pack and place it in the lamp unit.

The desiccant pack will absorb the moisture and prevent any water droplets formed in the lamp or blinker unit.

Periodically check the desiccant pack and replace it once every 6 months. The desiccant pack contains silica gel and it can only absorb a limited amount of moisture before the white gel turns into liquid. 

What are the different types of operating fluids in the car?

The different types of operating fluids used in a car are listed below.

  • Coolant

The Coolant used in the car is made up of ethylene glycol with some additives like anti-corrosion or anti-freeze. The coolant concentration can be checked with the help of a refractometer.

In hot countries, the coolant can contain up to 90 percent of water but the coolant concentration must have the correct percentage of antifreeze. Too much water in the coolant will freeze and there will not be any coolant flow in the cooling system.

The coolant reservoir has a built-in level sensor, and it only requires a top-up when there is a coolant level warning in the instrument cluster. Coolant must be renewed every 6-8 years or if the coolant is contaminated with engine oil due to a leak in the heat exchanger.

  • Windshield washer fluid

It is stored in a separate reservoir; the windshield washer fluid contains soapy water. An electric pump sprays the solution on the front and the rear windshield, and wipers are also actuated at the same time to clean the windshield.

It is possible to use normal water instead of windshield washer fluid but normal water can cause the wipers to judder on the windshield. The soapy water not only removes any dirt from the windshield but also helps to lubricate the wiper blades and prevent excessive juddering.

It is used to lubricate the moving parts in the engine; the level can be checked with the help of an oil dipstick. On some of the expensive models, there is an oil level sensor which measures the quality and level of engine oil.

There are other fluids like automatic transmission fluid, brake fluid and power steering fluid. These fluids have a long life and don’t require regular checks by the customer.


This blog gave information on operating fluids in the car and explained why water can enter the blinkers or other lamps on a car. There are plenty of automotive maintenance items available so it is necessary to know which are actually real and used to keep the car running in good condition.