Power Steering Fluid Cap Missing! – Temporary Solutions That Work!

Let’s not beat around the bush; driving without a power steering fluid reservoir cap can be dangerous. The cap is an essential component of the power steering system that prevents contaminants from entering the hydraulic fluid. Without it, debris such as dirt, dust, and water can contaminate the fluid, which will cause damage to the steering pump, steering rack, and other components. This can lead to a loss of power steering, making it difficult to steer the vehicle.

All of that doesn’t sound good, but there is a temporary solution that doesn’t just involve buying another cap. After all, that might not be possible immediately, and you probably need to drive the car to get one!

What Is a Power Steering Reservoir Cap?

The power steering reservoir cap is the lid that sits on top of this container, keeping the fluid inside and preventing dirt and debris from getting in; simple!

In addition to keeping the power steering fluid contained, the reservoir cap also helps to regulate the pressure of the liquid. This is important because too much pressure can cause the power steering pump to overheat and fail, while too little pressure can make it difficult to steer the car.

Can You Drive Without a Power Steering Reservoir Cap?

If you find yourself in a situation where your power steering reservoir cap is missing or broken, then you may need to drive the car without one. While this is possible it is if possible much better to make a temporary cap. However, if you find yourself needing to drive without the cap, there are some things to consider:

  • Risk of contamination – Without a cap, the power steering fluid is exposed to dirt, dust, and other contaminants that can cause damage to the power steering system. This can lead to an expensive repair down the line.
  • Loss of fluid: The cap helps to keep the power steering fluid in the reservoir. Without it, the fluid will leak out of the top even from just turning corners. If power steering fluid runs dry it can be difficult or near impossible to steer the vehicle, especially at low speeds.
  • Temperature changes: The cap also helps to regulate the temperature of the power steering fluid by keeping it under pressure. Without it, the fluid can overheat, which can cause damage to the power steering system.

Tips for driving without the power steering cap

  • Check the fluid level – Regularly pull over and ensure the power steering fluid is at the proper level. If it is low, top up with the recommended fluid.
  • Avoid driving off-road – Dirty dusty roads will encourage contaminants to enter the power steering fluid reservoir, which will cause issues.
  • Monitor the steering – Pay close attention to how the vehicle handles. Pull over and re-check the fluid level if you notice any unusual noises or difficulty steering.
  • Keep an eye out for warning lights – If the fluid level becomes too low, the power steering warning light will illuminate, you will need to pull over and top up the fluid immediately.

If you have driven without the cap, once you replace it with a new one, it would be wise to drain and replace the power steering fluid completely.

Temporary Solutions

Covering the power steering reservoir filler hole is the best solution to the missing cap. Once the reservoir hole is covered, there is minimal risk of damaging anything in the power steering.

You can use a few household items, such as aluminum foil wrapped around filler, a plastic carrier bag, and an elastic band to keep the new in place. Whatever you use, it needs to completely cover the filler hole and be secure enough to keep the fluid contained.

Do not use paper, regardless of what you decide to use to cover the reservoir.


The power steering fluid cap is critical; driving without one can cause damage to vital steering components. It is much more sensible to temporarily cover the reservoir with some household items to keep the fluid contained. At least then, you can drive the car to get a new cap!

My name is Tom although my friends call me Tommy. Messing around with cars and bikes has always been a hobby of mine even from a young age. So I made it my day job 17 years ago. I am a fully qualified mechanic as you would expect. I've worked in all different areas of the motor trade, valeting, panel beating, engine repairs, I'm sure you get the idea. I enjoy sharing my wealth of knowledge and experience with others, which is the reason I spend a lot of time here writing for this website.

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