Have you ever taken a peek at your car’s power steering fluid reservoir, and wondered; “why is my power steering fluid milky”? Well, if you have, then pay attention, as it can seriously impact your car’s steering.
Milky power steering fluid (which should normally be a translucent reddish or pinkish fluid) is a typical sign of serious issues such as water contamination, the presence of air bubbles, or a hydraulic systems failure.
Aside from this, I usually notice milky power steering fluid whenever there’s cross-contamination with your car’s other fluids, or the chemical breakdown of the power steering fluid, which can cause steering issues.
Therefore, here’s a breakdown of the 5 most common causes and reasons why your power steering fluid is milky (in order of the most common/typical culprit, down to the least):
- Presence of air bubbles
- Water contamination
- Hydraulic system failure
- Chemical breakdown
- Cross-contamination
Power Steering Fluid Color
First off, here’s a quick little cheat sheet on what color your car’s power steering fluid should normally be, and what different colors, textures, or conditions might entail:
- Reddish, Pinkish, Green, Blue, Or Clear – Healthy/Normal (Most power steering fluids are red, but some car brands and manufacturers tend to dye theirs a bit differently, usually to make diagnosing leaks a bit easier. Other than red, some are pinkish, green, blue, or entirely clear.)
- Milky Or Foamy – Unhealthy/Bad (This is not normal, and is often caused by water contamination, the presence of any air bubbles, hydraulic steering systems failure, cross-contamination with other fluids, or the chemical breakdown of the power steering fluid. While it’s not 100% deadly or serious, but still worth checking and diagnosing with a mechanic ASAP.)
- Brown Or Black – Unhealthy/Bad (This is usually the case that you haven’t changed the power steering fluid in a long time, and it’s a sign that your power steering fluid has worn out and needs a replacement. Brown entails heavy use, while completely darkened or black fluid shows that it’s too far gone. If you see this, an urgent fluid change is needed.)
- Yellow Or Light Brown – Really Bad (URGENT: If you see yellow fluid in your power steering fluid reservoir, this is typically a symptom that coolant has somehow leaked into your car’s power steering system. In this case, the power steering fluid needs to be flushed and replaced entirely, as it could severely impact your car’s steering system. NOTE: There are certain car brands that use yellow-dyed power steering fluid, so make sure that you check first.)
Cause #1: Presence Of Air Bubbles
Over time, the numerous seals and gaskets in your car’s power steering system can wear out or become damaged. This deterioration allows air to enter the system, leading to the formation of air bubbles.
These bubbles, when mixed with the power steering fluid, create a foamy, milky appearance. This not only changes the fluid’s color but also diminishes its hydraulic efficiency, impacting steering performance.
Low power steering fluid levels can also lead to air entrapment. When the fluid level drops, air occupies the space, getting churned into the fluid. This can happen due to leaks or inadequate maintenance.
FIX: When seals and gaskets are damaged or wear out over time, they should be replaced promptly. Elsewhere, ensure that your power steering fluid is filled to the recommended level. Regular checks and top-ups can prevent air entrapment, and in keeping a close eye on those seals and gaskets.
Cause #2: Water Or Moisture Contamination
Water and moisture in general can enter your car’s power steering system through leaks. These leaks might be in the power steering system’s hoses, connections, or the power steering pump itself.
Once water mixes with the steering fluid, it becomes less effective as a hydraulic medium and takes on a milky appearance. This is because water doesn’t possess any hydraulic characteristics.
A compromised reservoir cap could also fail to seal the system properly, allowing moisture or water from the environment to seep in. This moisture, over time, accumulates and contaminates the fluid.
FIX: Addressing leaks in your power steering system may involve replacing damaged hoses or connections and ensuring that all fittings are secure. Moreover, if the reservoir cap is damaged, replace it immediately to prevent moisture ingress.
Cause #3: Hydraulic (Power Steering) System Failure
Components within your car’s hydraulic power steering system, such as the pump or the hoses, can wear out over time. This wear and tear can lead to internal leaks within the power steering system.
This would allow air and possibly contaminants to mix with the power steering fluid. Excessive heat in the power steering system can cause the fluid to degrade and form emulsions with any present air or water.
Thus, this would lead to a milky appearance. Overheating can be a result of intense driving conditions or a failing power steering pump. Either of which isn’t an ideal scenario, and needs to be taken care of.
FIX: Replace any worn-out hydraulic components in the power steering system, such as the pump or hoses. Furthermore, it may require repairing or replacing the power steering pump or improving the cooling system to prevent fluid degradation.
Cause #4: Chemical Breakdown Of The Power Steering Fluid
Power steering fluid, just like any other fluid in your vehicle, has a lifespan. Over time, it can break down chemically, especially under high heat and pressure conditions, which puts additional pressure on it.
This chemical breakdown can lead to a change in color and consistency, resulting in a milky appearance. Otherwise, you might also notice the power steering fluid turning into a dark brown or black color.
FIX: Regularly change the power steering fluid according to the manufacturer’s recommendations. Using high-quality fluid and adhering to service intervals can also help to prevent chemical breakdown.
Cause #5: Cross-Contamination With Other Fluids
Sometimes, someone could accidentally mix other automotive fluids, such as coolant or brake fluid, with the power steering fluid. This usually happens due to improper maintenance practices or system leaks.
Such cross-contamination can change the appearance and properties of the power steering fluid. Just like the intrusion of water or moisture into the system, this will impact its inherent hydraulic properties.
FIX: If cross-contamination occurs, a complete flush and refill of the power steering system are necessary. You need to ensure that all fluids are correctly identified and filled in their respective reservoirs to prevent future incidents.
