Do You Put Brake Fluid in While Car Is Running?

Brake fluid is corrosive, and if it gets on your engine or other parts of your car, it can cause damage. The fluids that lubricate those parts are meant to be used for that purpose: preventing corrosion, not causing it.

If you’re looking for a reason why it’s not a good idea to put brake fluid in while the car is running, there are plenty: it can cause damage to your car’s engine; it can have an adverse effect on other liquids in your vehicle, and it might even make your brakes less effective.

How do you add brake fluid?

You can add brake fluid by taking the cap off of the reservoir and pouring it in there or by doing what we recommend: opening your hood, turning on your hazard lights, and putting a bucket under your car so that it will drip into the bucket instead of all over your driveway.

Why put it in while the car is running?

Brake fluid is a hydraulic fluid that works to hold your vehicle together by lubricating parts of the braking system. If you put it in while the car is running, however, you run the risk of damaging your engine.

The reason for this is that there is already a lot of heat and pressure being created inside your engine and when you add brake fluid to this mix, it can cause serious damage.

Is it safe to put brake fluid in while the car is running?

It depends. According to the experts, it’s only safe if you’ve got a newer car with a special reservoir for adding brake fluid. Otherwise, it could be dangerous. Brake fluid is extremely corrosive and can cause serious damage to your car’s internal components.

If you’ve got a newer model and the manufacturer has included a special reservoir for adding brake fluid, follow their instructions carefully when filling it up, and don’t put any more than what they recommend into your reservoir at one time.

If you’re unsure whether or not your car has a special reservoir for adding brake fluid, check with your mechanic before attempting to add any.

How much fluid should you add?

If you can’t remember the last time you checked your brake fluid, it’s time to check it again. Brake fluid is hygroscopic it absorbs water. When it absorbs water, it reduces the amount of frictional force between your brakes and their rotors.

This means that if there’s too much water in your brake fluid, your brakes won’t be able to stop your car as effectively as they should be able to. You can check for this by simply looking at the level of brake fluid in the reservoir if there’s too much moisture in there, it’ll have settled near the bottom.

If there’s not enough moisture yet, but you know that you haven’t been driving your car lately because of bad weather or other circumstances, then don’t worry about adding any more just keep an eye on things.

If there is too much moisture in the system already and you need to add more brake fluid, only add enough just so that all of it is visible above the filler hole then drive around for a while before checking again. If there’s still too much moisture after this time has elapsed.

What kind of fluid should you use?

When you’re making your car run, it’s important to use the right kind of fluid. Brake fluid is different from engine oil, and you’ll want to make sure you have the right kind for your vehicle.

Brake fluid is typically blue or red in color, and it has a very low viscosity it flows easily. This makes it ideal for use in a brake system because when you press on your brakes, you want them to be able to move smoothly and easily so that you can stop quickly. The low viscosity of brake fluid allows this to happen.

Engine oil is much thicker than brake fluid its viscosity is higher and it needs to be changed more frequently than brake fluid does. Engine oil lubricates moving parts in an engine so that they can turn without friction or wear.

It also helps keep the engine cool by reducing friction between moving parts that would otherwise generate heat if they rubbed together too hard.

Why you shouldn’t put brake fluid in while the car is running?

If you’re changing your brake fluid, it’s important to make sure that you follow the directions on the bottle. One of the most common mistakes people make is putting brake fluid in while the car is running.

The reason this is a mistake is that brake fluid is highly corrosive, and can cause serious damage to your car’s system if it gets into it while the engine is running.

It’s better to wait until the engine has cooled down and then change out your brake fluid so that you don’t have to worry about any corrosive damage happening to your vehicle.


Brake fluid is a very important part of your car’s brake system. You should always make sure you have enough brake fluid in your car, as it is essential for keeping your brakes working properly.

If you run out of brake fluid while driving, it can be very dangerous and cause you to lose control of your vehicle. If you are unsure about how much brake fluid you should put in your car, or if there is another part of the braking system that needs attention, take it to a mechanic for an inspection.

Steven Hatman
Steven Hatman

We break down every information into easy-to-understand articles that cover all the categories anyone who owns a car needs to know about, such as oil , brakes , tires and etc. Our car guide is free and updated regularly for you to use as a resource, not only when you have an issue with your car but even before buying a new or used car! We also give tips on what to look for in each category or part of your vehicle.