Is Putting Power Steering Fluid In While Your Engine is Running a Good Idea?

Your power steering fluid helps make it easy for you to turn your wheels, but like all vehicle fluids, the power steering fluid runs low, leaks, and needs to be replaced. You’ll usually know if you’re low on fluid, so if you need to add some quickly, can you do it while the car is running?

You can add power steering fluid while the car is running, but you may not want to. The pressure and heat running through the power steering system will most likely cause a mess, and you may end up with fluid on your clothes and engine bay. It is often best to add fluid while the car is off. 

This article will explore the pros and cons of putting power steering fluid in while the car is running. We’ll also give you some tips on how to do it without making a mess.

Adding Power Steering Fluid to Hot vs. Cold Cars

Most cars have a hot and cold fill level, so you can add fluid while the engine is either hot or cold. However, check your owner’s manual to be sure.

If you’re unsure, it’s always better to err on the side of caution and add the fluid when the engine is cold. This will avoid any potential messes and make it easier to see if there’s a leak.

The temperature of the power steering fluid matters because the fluid expands when it’s hot. This means that if you add fluid while the engine is hot, the level will be higher than it actually should be.

On the other hand, if you add fluid while the engine is cold, the level will be lower than it should be when the engine warms up. This isn’t a big deal, as you can top off the fluid when the engine is up to temperature.

Best Practices for Putting Steering Fluid in Your Car

You want to avoid getting power steering fluid on your clothes or skin because it can be irritating. It’s also a good idea to avoid spilling it on your engine bay, as it can damage paint and plastic, which is another reason to add fluid while the car is cold. 

In my experience, when my steering wheel was becoming hard to turn, I checked the fluid level and saw that it was low. I added some steering fluid, but I made a mistake–I forgot to turn off the engine first.

As I was adding fluid, pressure in the system spewed the fluid out, and it got on my clothes. It also got on the engine bay, which resulted in a mess that I had to clean up.

Of course, I could not clean the entire fluid from the bay, as it had seeped into nooks and crannies. This meant I had to bear with some unusual smells of power steering fluid burning off of the engine, and it lasted weeks.

The moral of the story: always turn off your engine before adding power steering fluid.

What Is Power Steering Fluid and What Does It Do?

Power steering fluid is a hydraulic fluid that helps steer your car easier. It does this by providing pressure to the power steering system, using a pump to push the fluid through hoses to the steering rack. 

Typically, there’s a belt in the engine that powers this pump, but new cars have a fully electric system that locks the wheels until you turn the car on. That means you might not have steering fluid in your vehicle.

Symptoms of Low Power Steering Fluid

The power steering setup rarely needs maintenance, but the fluid can go low over time. This is usually due to a leak somewhere in the system.

Here are some signs that you may be low on power steering fluid:

  • The steering wheel is hard to turn
  • The steering wheel squeaks when turning
  • The power steering pump is making noise
  • Fluid is leaking from the power steering system

If you notice any of these symptoms, it’s time to check your power steering fluid level. You can do this by looking at the reservoir. The fluid level should be between the “full” and “low” marks. If the fluid level is low, you’ll need to add more. 

What Happens if You Ignore the Low Power Steering Fluid Warning Signs?

If you ignore lower power steering fluid warning signs, the pump might start to suck air. This can cause a lot of damage to your power steering system and may result in expensive repairs. 

It’s also worth noting that the power steering fluid is a hydraulic liquid. This means it’s under pressure when it’s in the system. If there’s a leak, the fluid can spray out and cause injury. It’s also possible for the liquid to catch fire if it is sprayed onto a hot engine.

For these reasons, it’s important to check your power steering fluid level regularly and check what’s causing the loss. This can save you a lot of money and hassle in the long run.

How Often Should You Check Your Power Steering Fluid?

You should check your power steering fluid every few months or whenever you notice changes in your steering. This will allow you to catch any leaks early and avoid damage to the system. However, power steering fluid can last up to 4 years without needing a change. 

I drive a lot, so I like to check my power steering fluid level every two months. This gives me peace of mind and ensures that I won’t run into any problems down the road.

The fluid is inexpensive, so there’s no excuse not to check it regularly. A few dollars now can save you hundreds (if not thousands) of dollars in repairs later.

What Happens if You Put Too Much Fluid in the Power Steering System?

You might be tempted to overfill the power steering system if you’re worried about a leak. However, this is a bad idea.

If you put too much fluid in the power steering system, it can cause foaming. This can damage the pump and lead to steering problems. It’s also possible the liquid may overflow and make a mess.

For these reasons, it’s important only to add the required amount of fluid. If you’re not sure how much to add, check your owner’s manual or ask a mechanic.

Do Power Steering Fluids Have Different Colors?

Power steering fluid usually comes in two colors: red and clear. The color doesn’t affect the performance of the liquid, so you can use either one. However, most people prefer the clear one so they can tell the difference between transmission lube and power steering fluid.

Some manufacturers have special fluids, which means their cars will not work with anything else. For example, Honda has a power steering fluid. Adding a generic one to the Honda can cause issues.

If you’re not sure what kind of fluid to use, consult your owner’s manual or ask a mechanic.

Do You Need To Add Power Steering Fluid if There’s a Leak?

It’s a good idea to add fluid if there’s a leak, as this will help prevent damage to the system. However, you should first try to find the source of the leak and repair it. Otherwise, you’ll just be adding fluid regularly, which is not very convenient.

If you can’t find the source of the leak, take the car to a mechanic and have them take a look. They should be able to pressure test the system and find the source of the leak. A leaky line is an easy fix that anyone can pull off in minutes, but a reservoir or pump replacement will be expensive and labor-intensive.

Leaks usually happen at the seals, so that’s an excellent place to start looking. However, it’s also possible that there’s a crack in the reservoir or one of the lines.

Final Thoughts

You can add power steering fluid while the car is running. However, as a pressurized system, fluid may expel from the reservoir and get on your engine, clothes, or other car parts. You can add fluid whether the engine is hot or cold, so you don’t have to wait for your car to cool off. 

Adding fluid is relatively simple, and it’s wise to check the fluid levels every once in a while, especially if you notice odd behavior with your steering system. If you discover a leak, it’s best to investigate it quickly to avoid expensive repairs.


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