Understanding the Mysteries of Green Power Steering Fluid

Power steering fluid plays a crucial role in a vehicle’s steering system, ensuring smooth and responsive steering operations. Under normal circumstances, this essential fluid exhibits a red or amber color, signifying its optimal condition. 

However, there may be instances when the power steering fluid turns green, an occurrence that raises both eyebrows and concerns among vehicle owners. 

This article delves into the reasons behind this unusual color change, and its potential implications for your vehicle’s performance and longevity. 

Understanding these factors can equip you with crucial knowledge to maintain your car’s health, ensuring it continues to serve you efficiently and reliably. Let’s explore this intriguing topic in detail.

Common Colors and Causes of Power Steering Fluid 

Typically, power steering fluid presents in a range of colors—from clear to amber or sometimes red, depending on its age and the additives that have been mixed into it by the manufacturer. 

These additives are essential in preventing oxidation, reducing foaming, and enhancing the fluid’s lubricating properties. 

However, several factors can cause the fluid color to change. For instance, it might darken due to contaminants from worn-out components or degraded additives. An internal leak might also result in chemical reactions that cause the fluid to discolor. 

Once, while preparing for a long-anticipated road trip, I noticed my car’s power steering fluid had turned a concerning shade of black

This discovery led to a quick trip to the mechanic, revealing that degraded additives and contaminants from worn-out components were the culprits. It was a timely reminder about the importance of regular car maintenance.

The Unusual Green Transformation

Green power steering fluid is not a common sight, and its appearance should trigger immediate attention. 

This unusual color often signifies a coolant contamination issue—the result of a leak where coolant finds its way into the power steering system. The leak could be due to faulty gaskets or seals, or even due to mishaps during maintenance or repairs.

While uncommon, I’ve encountered this green transformation a couple of times in my years of driving. In one such instance, my friend’s car had green power steering fluid, which we eventually traced back to a coolant leak. 

The situation was resolved by replacement of the faulty parts, but it was certainly a learning experience about the importance of maintaining vehicle health. 

Remember, while these color changes can be alarming, they also serve as important indicators of underlying issues that need to be addressed promptly to prevent further damage to your vehicle. When in doubt, always consult with a professional mechanic or your vehicle manufacturer.

Eight Reasons Power Steering Fluid Turns Green

1. Contaminated Fluid 

It’s a well-known fact that fluids in your car should not mix unless designed to do so. If other fluids like coolant or transmission fluid find their way into the power steering system, they can contaminate the power steering fluid. 

The mixture of these fluids often results in a greenish color. From personal experience, I’ve seen this happen when a worn seal allowed transmission fluid to leak into my power steering system. 

The mechanic identified the green tint and we managed to replace the seal before the contamination could cause serious damage.

2. Coolant Contamination

The coolant system and the power steering system in your vehicle are separate systems. However, a leak could cause coolant to infiltrate the power steering system. 

When coolant mixes with power steering fluid, it can result in a color-changing effect, often leading to a green hue. As I mentioned earlier, a friend’s car had this exact issue.

3. Use of Universal Fluids

There are specific fluids designed for each system in your car. Using universal or non-specific fluids in the power steering system can lead to color changes. 

These fluids often contain different dye additives which, when mixed with the original fluid, can create a green color. 

I’ve seen this happen when a fellow car enthusiast used a so-called “universal fluid” in his power steering system, which ultimately turned green.

4. Additive Degradation 

Power steering fluid contains additives to enhance its performance. Over time, heat, contaminants, or extended use can break down these additives. 

This degradation can lead to a change in the fluid color, often resulting in a green tint.

5. Chemical Reactions 

In rare instances, chemical reactions between fluids within the power steering system can happen. 

This typically occurs when the wrong type of fluid is used or if the fluid is old and has been subjected to high temperatures. These reactions can result in a greenish color.

6. Microbial Growth

If there’s moisture or water in your power steering system, it could lead to microbial growth. Certain microorganisms create byproducts that can give the fluid a green hue. 

While unusual, I’ve heard of cases where this has happened, particularly in older, poorly maintained vehicles.

7. Corrosion and Oxidation

Over time, metal components in the power steering system can corrode or oxidize. This can result in the presence of rust particles in the fluid, contributing to a greenish tint. 

I’ve personally seen this on a classic car I was restoring, where the old, corroded pipes had caused the power steering fluid to turn a greenish color.

8. Manufacturing Variations 

Lastly, inconsistencies in fluid manufacturing can sometimes result in unexpected color changes. 

In rare instances, the power steering fluid might turn green due to these variations. While I haven’t personally experienced this, it’s important to consider all possibilities when dealing with a change in fluid color.

Addressing the Issue

Ignoring the green tint in your power steering fluid can lead to significant problems down the line. It’s important to promptly address any changes in your fluid to prevent potential damage to your power steering system. 

If unsure about the cause of the green tint, consulting your vehicle’s manufacturer or a professional mechanic is recommended. 

They have the expertise to accurately diagnose and resolve the issue, ensuring your vehicle’s power steering system remains in optimal condition.


In conclusion, understanding why your power steering fluid may turn green is crucial in maintaining your vehicle’s health. 

We’ve discussed several possible causes – contamination, additive degradation, chemical reactions, microbial growth, corrosion and oxidation, and manufacturing variations. 

By identifying these potential problems early, you can prevent serious damage to your power steering system. 

Be proactive in monitoring your vehicle’s power steering fluid, and don’t hesitate to seek professional help when needed. Your vehicle’s longevity and performance depend on it!

Frequently Asked Questions

Q: What is the difference between red and green power steering fluid?

A: Red power steering fluid is typically used in older vehicles, while green power steering fluid is found more commonly in modern vehicles. The type of fluid to use should be determined by your vehicle’s manufacturer. 

Q: What does it mean when my power steering fluid turns green?

A: A green tint could indicate contamination, additive degradation, chemical reactions, microbial growth, corrosion, oxidation, or manufacturing variations. It’s important to identify and address the cause promptly to avoid any damage to your power steering system.

Q: How does contamination affect the color of my power steering fluid?

A: Contaminants such as water, coolant, or other automotive fluids can cause your power steering fluid to change color due to chemical reactions.

Q: Can I ignore the green tint in my power steering fluid?

A: Ignoring color changes in your power steering fluid can lead to significant issues over time. It’s recommended to consult with a professional mechanic or your vehicle’s manufacturer to diagnose and resolve the issue.

Q: What steps should I take if I notice a change in the color of my power steering fluid?

A: If you notice a change in your fluid’s color, the first step is to stop driving your vehicle and check the power steering fluid reservoir. If you’re uncertain about the cause of the color change, seek professional help immediately.

Q: How does microbial growth affect my power steering fluid color?

A: In rare cases, microbial growth can cause your power steering fluid to turn green. This usually happens if the fluid has been sitting idle for a long period or if the vehicle’s storage conditions are unfavorable.

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