Yes—use the fluid your vehicle manufacturer specifies. Most traditional hydraulic power steering systems run on ATF, but some models require a dedicated power steering fluid (non-ATF). Electric power steering does not use hydraulic fluid at all.
Understanding power steering fluids
Power steering systems rely on hydraulic fluid to transmit pressure and lubricate components. There are two common configurations: systems that use automatic transmission fluid (ATF) and those that require a dedicated power steering fluid (PSF). Electric power steering (EPS) eliminates the hydraulic side entirely, but not every car on the road uses EPS yet.
Two main configurations to know
Common power steering configurations fall into two categories. Here is a concise breakdown of what you might encounter:
- ATF-based power steering systems: In many vehicles, the steering system uses ATF because the hydraulic circuit shares the same fluid as the transmission. If your manual specifies ATF for the PS system, you should use the correct ATF grade and follow the service guidelines.
- Dedicated power steering fluid (PSF): Some makes require a non-ATF hydraulic fluid with a specific additive package designed for steering components. Do not mix PSF with ATF unless the manual explicitly allows it.
Knowing which category applies to your car helps avoid damage and ensures consistent steering performance. When in doubt, consult the owner's manual or a dealership.
How to determine the exact specification for your vehicle
To identify the correct fluid for your car's power steering system, follow these steps:
- Check the owner's manual or the under-hood label for the exact fluid type and specification (ATF vs dedicated PSF, and any required viscosity or brand notes).
- Note whether the specification calls for ATF or a non-ATF PSF and whether there are any compatibility notes about mixing with other fluids.
- If the manual lists ATF, ensure you source ATF that meets the specified specification for your vehicle (do not assume all ATFs are interchangeable).
- If the manual lists a dedicated PSF, use only that PSF and avoid mixing with ATF unless the manual states it is acceptable.
- If you cannot locate the specification, contact the dealership, a trusted mechanic, or the manufacturer's technical support for guidance.
Having the exact specification on hand helps ensure proper performance and protects seals and pumps from premature wear.
Common mistakes to avoid
Even when you know the right type, people often make avoidable mistakes when topping up or changing power steering fluid.
- Mixing different types of fluid (ATF with PSF) unless the manufacturer explicitly allows it.
- Using the wrong viscosity or an older/incorrect formulation that can degrade seals or reduce steering feel.
- Topping up but not addressing a leak; low fluid often signals a leak that needs repair.
- Assuming “lifetime” fluid means no maintenance; some systems still benefit from periodic checks or changes, especially after repairs.
- Neglecting to wipe the reservoir cap and avoid dirt contamination when opening the system.
Sticking to the manufacturer's guidance will help preserve steering performance and prevent costly damage.
Special case: electric power steering (EPS)
Many modern vehicles use EPS, which does not rely on hydraulic fluid for steering assist. EPS systems still require occasional maintenance and may have electrical or hydraulic components that need checks, but they do not use PS fluid in the same way as hydraulic systems. Always verify whether your car uses EPS and follow its maintenance schedule.
DIY tips and when to call a pro
Small top-ups can often be done at home if you have the right fluid and a clean reservoir. However, a full flush or replacement, leaks, or uncertain specifications are best handled by a professional.
- Park the car on a level surface and turn off the engine with the parking brake set; allow the engine to cool if recently driven.
- Check the power steering reservoir for the current fluid level and examine the fluid color for signs of contamination (dark, gritty, or milky fluid should be replaced).
- With the engine off, add the recommended fluid gradually, using the correct type specified by the manufacturer; do not overfill.
- With the engine running at idle, turn the steering wheel from lock to lock several times to circulate the new fluid; recheck the level and top up if necessary.
- If you notice leaks, unusual noises, or excessive effort during steering, stop and seek professional service.
These steps help you perform a careful top-up or initial flush, but professional service may be necessary for a full fluid change or line repair.
Summary
The key takeaway is simple: always use the fluid specified by your vehicle’s manufacturer. If the spec calls for ATF, use the appropriate ATF; if it requires a dedicated PS fluid, use that only. EPS vehicles do not use hydraulic PS fluid. When in doubt, consult the manual or a trusted technician to avoid damage to seals, pumps, and steering feel.