Can you Pressure Wash your Engine Bay?

Last Updated on July 5, 2021

Is it okay to pressure wash your engine?


People say that you can tell a lot about a person based on how clean their car is. We love to keep our cars nice and clean, regardless of whether it’s a new or old motor. But the question is can you pressure wash your engine bay?

Pressure washing the exterior of the car is an absolute must in our opinion, but have you ever wondered whether it is okay to pressure wash your engine?

It’s obviously a good idea to keep your engine clean as this prevent build up of grime and helps your engine last longer!

However, when it comes to pressure washing your engine, it’s normal to feel precautious. The engine is the most important part of your car and consists of a combination of mechanical and electronic parts.

Many people feel like spraying water into the engine bay would be disastrous for your car – after all, surely the water will leak into the electronics and cause all sorts of problems?

Well, you might be pleasantly surprised – we are here to tell you that when it comes to modern cars, pressure washing your engine is absolutely fine.

These days, car engines are designed in mind of things such as this. Any electronics will be securely waterproofed to prevent any potential damage, and mechanical elements will take the water with no problems at all.

However, there are risks present when it comes to pressure washing your engine bay, but it’s not to do with the water. Instead, it’s the pressure of the water itself.

High water pressure can be damaging to fragile parts of your engine, and irresponsible use of a high PCI pressure washer could cause more damage than good.

So, to answer your question, it is absolutely fine to wash your engine with a pressure washer, but you’re going to want to do this carefully. Lucky for you, we’ve provided this step-by-step guide of things to consider!


How to pressure wash your engine bay

The first thing that you are going to need to consider before you begin pressure washing your engine bay is the age of your car. As we already mentioned, if you’re looking to spray the engine of a modern car then everything should be waterproof and safe.

However, if you own a vintage or modified car, spraying water into the engine may not be appropriate.

Depending on the age of the vintage car, some of the engine parts may not be waterproof. Furthermore, even if the engine is fully waterproof, the waterproof lining may have deteriorated over time rendering it useless.

Finally, consider whether your engine is modified in any way. Car manufacturers take great care in ensuring their engines are waterproof, but manufacturers for custom engine parts and mods may not take the same precautions!

Once you are satisfied that your car engine is waterproof and suitable for being sprayed with water, it’s time to get the pressure washer out! However, high amounts of pressure really is not advised for this job.

Therefore, you are going to want to put away the pin-point attachment and replace it with the variable-pressure nozzle.

Turn that pressure right down – we know this sounds counter-intuitive, but high levels of water pressure can potentially be damaging to fragile parts of your engine.

You don’t need to worry too much, but use basic common sense. For example, blasting your alternator with 2,500 PSI of water is probably not the brightest idea.

Once you have turned the pressure down, give the engine a good spray down, making sure you cover any elements that you are concerned about.

Feel free to apply some degreaser and get a wooden brush to help aid the pressure washer in removing that nasty grime. Once the job is done, consider using a can of compressed air to blow away any remaining residue.


What to be careful of when pressure washing your engine bay



If you own a car manufactured in the last 50 years, all the electronics should be cased off and waterproof. However, it’s still essential that you practice common sense and don’t go blasting electronic components with huge amounts of water pressure.

This is more due to the impact rather than the water – high PCI pressure washers could easy break wiring or other electronic components. Save your high-pressure attachments for the really dirty jobs and take it easy when it comes to cleaning electronic components.

Aim to get a water pressure level like that of a standard gardening hose pipe – this is unlikely to do any damage to your electrics!



We have always been taught from a young age to never combine water and electronics, so it is absolutely normal to be hesitant when it comes to getting water on your car battery.

It may seem intuitive to disconnect the battery from the car to ensure that no electricity is present at the time of the wash.

However, this really is not necessary. The car manufactures anticipated this cleaning and will have ensured that your battery is appropriately cased off and waterproof.

However, it may be wise to take a look at your battery before commencing to ensure that it’s in good condition and without any visible damage.


Pipes and Bolts

When it comes to cleaning metallic elements such as pipes and bolts, you can be a little bit more liberal with your water pressure.

High-pressure attachments such as the pin-point nozzle are excellent choices for cleaning metal, but you want to ensure that your accuracy is excellent and you don’t accidentally blast fragile components!

Furthermore, it’s probably worth keeping fancy detergents away from metallic elements. They can be great for your cars exterior, but when it comes to metal can often cause rust.

This rust can eventually build up and potentially cause a much bigger problem than a dirty engine!


Final Thoughts

Overall, cleaning your engine bay with a pressure washer can be quite nerve-racking, but you don’t have to worry so much!

As long as your car was designed in the last 50 years or so, any electronic components in your engine should be waterproof and out of the way.

However, it’s very important to assess your engine for anything out of the ordinary, in addition to ensuring that you don’t blast fragile electronics with high water pressure.

In conclusion, it’s probably best to safe the high-pressure attachments for another job – regular water pressure, degreaser and a wooden brush will be just fine for this job. Practice basic common sense, and your engine will be good as new in no time!

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