Most cars except some electric and hybrid vehicles have a hydraulic power-steering system that enables the driver to turn the steering wheel without a great deal of effort. The power-steering system consists of several items: a rack and pinion connected to the front wheels; a piston inside the rack and pinion, which is moved by pressurized fluid from the power-steering pump that helps to turn the wheels; and a cylinder containing fluid mounted on the pump or remotely mounted for easier access. (If there isn't enough fluid, steering becomes more difficult and either the pump or rack and pinion could be damaged without fluid to cushion them.) Therefore, it's important to check power-steering fluid levels on a regular basis and add fluid when necessary.

Steps

  1. 1
    Look for the reservoir cylinder. If you're having difficulty turning the steering wheel or a high-pitched whining noise issues from the steering wheel when you turn it, chances are your power-steering fluid is low. The power-steering fluid can be found in a cylindrical reservoir near the power steering pump or remotely located with hoses from the pump, and should be clearly labeled. The cylinder may be made of either plastic or metal.
  2. 2
    Check the level of the power-steering fluid. If the reservoir cylinder is made of translucent plastic, you may be able to see the fluid level inside the cylinder. If the reservoir cylinder is made of metal, or if the plastic is not sufficiently transparent, you'll check the fluid level with a dipstick, which is usually attached to the cap.
    • On some cars, the power-steering fluid level can only be checked accurately after the engine has run for a brief period, and sometimes you must also turn the steering wheel in either direction several times while the car idles.
    • On other cars, there are gradations on the dipstick or cylinder for both a "hot" level, after the engine has been running, and a "cold" level, after the engine has been off for a period of time. On still other cars, there may be "Min" and "Max" lines for acceptable fluid levels. Be sure to compare the power-steering fluid level against the correct mark.
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  3. 3
    Examine how much of the dipstick is covered by power-steering fluid. If you are using a dipstick to test the power-steering fluid level, first wipe off any excess fluid from the dipstick when you first take it out of the cylinder, then reinsert it as far down as it will go and pull it out again.
  4. 4
    Examine the color of the power-steering fluid. Good power-steering fluid should be clear, amber or pinkish in color.
    • If the power-steering fluid is brown or black, it has been contaminated with bits of rubber from connecting hoses, seals or O-rings. In this case, the car should be taken to a mechanic to see if any of the power-steering system parts need to be replaced, along with the fluid.
    • The power-steering fluid may look darker than it actually is. If you have any doubts, look at the color of the power-steering fluid stain on the rag or paper towel you wiped your dipstick off with. If the stain is the color the fluid is supposed to be, your fluid is not contaminated.
  5. 5
    Add power-steering fluid as needed to the correct fill level. If your car has gradations on the cylinder, you can add the fluid steadily until you reach the correct "hot" or "cold" fill level; if you checked the level with a dipstick, add the fluid incrementally to avoid overfilling the reservoir.
    • Be sure to use only the power-steering fluid that is recommended for your car, as it will be the correct viscosity (thickness) for your car's power-steering system.
    • The manufacture does not recommend using transmission fluid in place of power steering fluid. There are too many different types of fluid, and if the wrong fluid is used, it may cause failure of power steering and its seals.
    • Be careful not to overfill your power-steering unit with fluid. It's probably better to under fill your unit than overfill it. That's because power-steering fluid expands as it heats up and works its magic. If you fill your unit all the way to the top and then try to drive your car, the expanded pressure could begin to cause problems and might necessitate expensive repairs.
  6. 6
    Replace the cylinder cap. Depending on the make of car, you may have to push or screw the cap into place. Be sure it's firmly attached before you close the hood.
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Warnings

  • Power-steering fluid should also be replaced at the intervals called for in the car's owner's manual. Heat from the engine and surrounding environment will, over time, reduce the fluid's ability to do its job and cause wear and tear on the power-steering system components. Replacing the fluid is cheaper than having to replace either the power-steering pump or the rack and pinion.
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  • Not all cars take "generic" power steering fluid; search online or your owner's manual for the specifications on the proper fluid for your car.
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Things You'll Need

  • Rag or paper towel
  • Funnel
  • Power-steering fluid

References

  1. Hovig Manouchekian. Auto Repair & Design Specialist. Expert Interview. 23 February 2021.
  2. Hovig Manouchekian. Auto Repair & Design Specialist. Expert Interview. 23 February 2021.
  3. Hovig Manouchekian. Auto Repair & Design Specialist. Expert Interview. 23 February 2021.
  4. http://news.carjunky.com/car_maintenance/how-to-check-power-steering-fluid-cdh085.shtml
  5. http://www.automd.com/40/how-to-check-power-steering-fluid/
  6. Rodney Ruff, Omaha, NE; personal experience in dealing with rack and pinion leak

About This Article

HM
Co-authored by:
Auto Repair & Design Specialist
This article was co-authored by Hovig Manouchekian. Hovig Manouchekian is an Auto Repair and Design Specialist and the Manager of Funk Brothers Auto, a family-owned business operated since 1925. With over 30 years of experience in the automotive industry, Hovig specializes in the process of auto repair and maintenance. He is also very knowledgeable in common automotive issues and needs including engine repair, battery replacement, and windshield accessory and maintenance. Hovig's knowledge and hard work have contributed to Funk Brothers Auto winning Angie's List Super Service Award for five consecutive years. This article has been viewed 1,106,022 times.
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Co-authors: 14
Updated: January 23, 2023
Views: 1,106,022
Article SummaryX

To check and add power steering fluid, start by locating the reservoir cylinder near the power steering pump. Then, if the cylinder is made out of clear plastic, check the level of the fluid to see if it's low. If the cylinder isn't transparent, remove the cap and examine the dipstick to see if it's low. Next, if your car needs more power steering fluid, pour some into the reservoir cylinder until it reaches the right fill level. Finally, place the cap back on the cylinder. For more tips from our Mechanic co-author, like how to check the color of your power steering fluid to see if it's contaminated, scroll down!

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