How to Check and Add Power Steering Fluid
Compiled and fact-checked from cited sources, reviewed by our editorial team.
If your steering suddenly feels heavy, or you hear a whine or moan when you turn the wheel, low power steering fluid is one of the most common causes. Checking the level and topping it off is a job you can do at home in a few minutes — but three things matter before you start: whether your car actually uses hydraulic power steering at all (many newer cars use electric steering with no fluid), whether you have the correct fluid type, and never putting the fluid in the wrong reservoir. This guide walks you through reading the level correctly with the engine on or off and hot or cold, how to add fluid, and exactly what to do if “I added fluid but it still turns hard,” “I put in too much,” or “I accidentally poured it into the brake reservoir.”
First: does your car even have hydraulic power steering?
Don’t skip this step. Most cars built in the last several years use electric power steering (EPS), and that system has no hydraulic fluid — there is no reservoir to check or top off.[2] If you can’t find a cap labeled “power steering” under the hood, or your owner’s manual describes electric steering, stop looking for fluid — your steering issue is with the electric system and that’s a job for a shop. The rest of this guide is for cars with hydraulic (or electro-hydraulic) power steering.
How to check power steering fluid
- Engine off, car on level ground. The fluid is usually checked safely with the engine cold.[1]
- Find the reservoir. It’s typically on or near the power steering pump and usually has a steering-wheel symbol on the cap.
- Read the level.
- See-through reservoir: read the MIN–MAX (or HOT–COLD) lines molded into the side.
- Sealed/metal reservoir: pull the dipstick built into the cap, wipe it, reinsert it, and pull it again to read the level.
- Check the fluid’s condition. If it looks dark brown or smells burnt, the fluid is old — it needs changing, not just topping off.[2]
- If the level is at or below the ADD/MIN line, top it off and look for a leak — this fluid doesn’t disappear on its own.
Engine on or off, hot or cold? For a safe, accurate reading, turn the engine off. If your reservoir has separate HOT and COLD marks: use the COLD line if the car has sat unused for more than 8 hours; use the HOT line if you've just been driving (once the fluid has warmed up and expanded). To check it hot, start the engine and turn the wheel fully lock-to-lock a few times to warm the fluid, then shut the engine off and read it.[[4]](https://engineerfix.com/do-you-check-power-steering-fluid-hot-or-cold/)
Adding fluid and common situations
- WhyWrong fluid swells/damages seals and causes leaks
- FixBleed the air out; check for leaks/pump
- FixUse a syringe/turkey baster to bring it to MAX
- FixDon't drive or press the brake; extract it + flush the system
How to add power steering fluid
- Choose the correct fluid. Use the type your owner’s manual calls for — some cars need a dedicated power steering fluid (PSF), others use ATF (automatic transmission fluid). They’re different classes of fluid, and using the wrong one damages seals (see below).
- Open the cap and add fluid a little at a time with a clean funnel.
- Don’t go past the MAX line. Stop often to check the level; do not overfill.
- Close the cap tightly. Start the engine, turn the wheel lock-to-lock a few times, then recheck the level.
”I added fluid but it still turns hard”
If the steering is still heavy after you’ve topped it off, the most likely cause is air trapped in the system. The pump chops the air bubbles into a foam, and foam can’t build pressure.[5] To bleed the air out:
- Let the car rest for a while (ideally overnight) so the bubbles rise into the reservoir.
- With the engine off, turn the wheel fully lock-to-lock several times; top the fluid back to between MIN and MAX as the level drops.
- Repeat patiently — bleeding air takes time.
If it still won’t improve, you may have a fluid leak (a hose or pump seal) or a failing pump — see a mechanic.
”I added too much”
Too much fluid can foam and leak past the cap or seals. Draw the excess out of the reservoir with a syringe or fluid extractor (turkey baster) until the level is back at the MAX line. (The same logic applies to engine oil — there’s a link to that guide below.)
The most dangerous mistake: putting it in the brake reservoir
Power steering fluid and brake fluid are completely different and can never be used in place of each other. If you accidentally pour power steering fluid into the brake reservoir, this petroleum-based fluid swells every seal in the brake system and causes brake failure — a serious safety hazard.[3]
If you've done this: Do not start the car and do not press the brake pedal. Immediately draw out as much fluid as you can with a syringe/extractor. Then the brake system (master cylinder, lines, calipers) must be completely drained, flushed, and bled — that's a shop job. Do not drive the car in this state.
Which fluid? ATF or dedicated PSF?
Systems are engineered for a specific fluid based on factors like viscosity, temperature range, and acidity. The wrong type causes trouble:
- Plain PSF in a system that needs ATF → not enough lubrication, and noise on sharp turns.
- ATF in a system that needs PSF → ATF’s high detergent content swells and degrades the seals designed for standard PSF; over time this leads to a rack leak and an expensive repair.[6]
The rule is simple: use whatever the manual specifies. In an emergency you might get by on the wrong fluid for a very short distance, but the system should be flushed with the correct fluid as soon as possible.
What happens if it runs low? Symptoms
- Heavier steering (especially at low speed, like parking)
- A whine, moan, or groan when turning, growing louder with the steering angle
- Foaming and a burnt smell
- Driving on low fluid for a long time causes permanent wear/damage to the pump and system.[2]
This fluid doesn’t drop on its own; if it keeps going down, there’s a leak — find the source.
Quick summary
| Question | Short answer |
|---|---|
| Engine on or off? | Off (safe + accurate reading) |
| Hot or cold? | COLD if sat 8+ hours; HOT mark if just driven |
| Which fluid? | Per the manual: dedicated PSF or ATF (don’t mix) |
| Added too much | Draw it down to MAX with a syringe |
| Added fluid, still heavy | Air in the system → bleed it; else leak/pump |
| Put it in the brake reservoir | Don’t drive! Extract + flush the brake system (shop) |
| Electric power steering | No fluid — nothing to check or add |
Other fluids in car maintenance
Power steering fluid is just one of the fluids you should check regularly. For the most important one — engine oil — see when and how to change it in our how to change car oil guide, and learn why overfilling is risky in too much engine oil: what happens.
Frequently asked questions
Do you check power steering fluid with the engine on or off? Check it with the engine off for a safe, accurate reading. The car should be on level ground and it’s usually checked cold; if your reservoir has separate HOT/COLD marks, use the right line for the situation.
Should you check power steering fluid hot or cold? If your reservoir has both HOT and COLD marks: use the COLD line if the car has sat for more than 8 hours, and the HOT line if you’ve just been driving (once the fluid has warmed and expanded). If there’s only one set of marks, keeping it between MIN and MAX is fine.
How do you add power steering fluid? Pick the correct fluid type from your owner’s manual, open the cap, and add a little at a time with a clean funnel without going past the MAX line. Check the level often so you don’t overfill, then start the engine, turn the wheel lock-to-lock, and recheck.
I added fluid but the steering still turns hard — why? The most likely cause is air trapped in the system; when the pump foams the fluid, it can’t build pressure. Let the car rest, then with the engine off turn the wheel fully lock-to-lock several times and top the level back up. If it doesn’t improve, you may have a leak or a failing pump.
I put in too much power steering fluid — is that bad? Too much fluid can foam and leak past the seals. Use a syringe or fluid extractor to draw the excess out of the reservoir and bring the level back down to the MAX line.
I accidentally put power steering fluid in the brake reservoir — what do I do? Don’t start the car and don’t press the brake pedal; power steering fluid swells the brake seals and can cause brake failure. Immediately draw out as much as you can with a syringe, and have the brake system completely flushed and bled — that’s a shop job.
Is ATF the same as power steering fluid? No, they’re different classes of fluid. Some cars need dedicated PSF, others use ATF. The wrong type can cause poor lubrication, noise, and especially seal swelling and leaks, so always use the fluid your manual specifies.
I can’t find a power steering reservoir on my car — why? Your car most likely has electric power steering (EPS), and those systems have no hydraulic fluid or reservoir. Any steering issue is with the electric system and needs a shop.
Sources
- YourMechanic — How to Check Your Power Steering Fluid Level. https://www.yourmechanic.com/article/how-to-check-your-power-steering-fluid-level-by-jerel-lawrence
- AMSOIL — How to Check Power Steering Fluid (and When to Change It). https://blog.amsoil.com/how-to-check-power-steering-fluid-and-when-to-change-it/
- CarParts.com — Accidentally Put Power Steering Fluid In Brake Fluid Reservoir? https://www.carparts.com/blog/accidentally-put-power-steering-fluid-in-brake-fluid-reservoir-how-to-fix/
- Engineer Fix — Do You Check Power Steering Fluid Hot or Cold? https://engineerfix.com/do-you-check-power-steering-fluid-hot-or-cold/
- AutoNation Mobile Service — How to Check Power Steering Fluid. https://www.autonationmobileservice.com/i/blog/how-to-check-power-steering-fluid/
- AutoFix — Is ATF the Same as Power Steering Fluid? https://autofix.blog/is-atf-the-same-as-power-steering-fluid