Is It Safe To Use Water To Clean Your Engine?


Is It Safe To Use Water To Clean Your Engine?

We recently shot a video for our #KasiBikin series about performing a thorough engine cleaning and detail on my own (SV4) Honda Accord. Since we now have more time for DIY projects at home given the extension of the MCO, we felt this could be one of those projects most people can do for their cars.

But can you/ should you use water to wash your engine? More so with your garden hose? 

Now in order to address those questions as well as some of our reader's comments and more, we present this article to shed more light on the matter. 

First, why do we have to clean our engine?

Well, it's simple, a clean engine will look great, run smoother and work better in the long run.


Cleaning your engine also removes grime that is lodged around belts, pulleys, and other components such as your radiator. Cleaning out your engine will ensure these parts run more efficiently.

Can I use water to clean my engine?

The short answer is yes.

Water is the most efficient way of dispelling and rinsing off all the dirt from your engine bay. One must understand that an engine is designed as a sealed and enclosed system (regardless of the make or model), not just to keep water out of sensitive components and mechanisms, but also dust, dirt, oil, and grime that is naturally picked up when we drive our cars.


Depending on the type of vehicle, manufacturers also wade the vehicle through water, to ensure that the car is properly sealed off in case you drive through a flood or a rainy day. Of course, vehicles such as pickup trucks and SUVs will be able to handle more water, but the same considerations are present even with a small hatchback.

There are a few clauses to the subject which we will get into, but, the most important aspect is knowing when and where to use water to clean your engine, and where you shouldn’t.


Professional detailers all over the world use water (even pressurised water) to clean engines, but the difference is they know when to use it and when not to.

However, before we go any further, let us enjoy the video below to better understand what engine detailing is and just how satisfying a clean engine bay looks.  

Then, what’s all the fuss about?

Well, in most cases, people are told not to clean their engines, especially by themselves, because they may shoot water into sensitive electrical components such as the electrical connectors, distributor, spark plug coils, fuse box, air intake, and sensors that are present in most modern engines. Therefore, it is more important you know where to use water, and just how much to use.


Moreover, if you do shoot water (especially at high pressure) into electrical connectors or the car’s intake system you can damage certain components or the engine.

Therefore, we do advise that you should be at least familiar with an engine and its major components before you decide to try a thorough clean on your engine. If not, you can always use a damp cloth and a spray bottle (with water or cleaning solution) to great effect. Certain engine cleaners in the market are also safe to be used on electrical components, so it pays to do your research and use the right products.


So yes, you do have to be mindful of certain components, and isolate them as best you can before beginning the cleaning process.

So, what do I have to isolate?

Have a good look around your engine first; identify any electrical connectors, ignition system components, and the air intake.

Once you have, you can use plastic bags, Ziploc bags, or even Shrinkwrap (recommended) to protect these components. Spend some time on this and properly ensure you have closed any potential points of water entry.


Now you know where these components are, it is best not to use excessive water in these areas. Use a spray bottle or damp cloth, or you can wash the other areas in your engine and come back to this once you have done the rest of the engine.

Okay, that’s done, what do I need to use to clean my engine?

There are a tonne of engine degreasers, cleaners and protectants. If you’re unsure buy premixed from notable brands and follow the instructions carefully.

Besides that, you’ll need some items to clean the surfaces in your engine. Use a sponge or cloth for the larger surfaces, while a toothbrush or small paintbrush is handy to get into the hard to reach spots.

With a degreaser you’re not actually scrubbing the surface, rather agitating the solution and letting it do the job, so there’s no need to be forceful.

Lastly, wear gloves to protect your hands, as some degreasers are quite potent, wear a facemask so you will not inhale any harmful substance or gases, goggles will protect your eyes, and finally clean your engine in an open or well-ventilated area.

Can I use a water jet if I have one?

You could, but we would caution you against using a water jet simply because the high pressure and velocity increases the chances of moisture getting into sensitive components such as the fuse box and sensors. A water jet also shoots finer droplets of water at the engine, again making it easier to enter components where it shouldn’t.


Although a water jet is an effective cleaning tool, our advice is just to use running water from a hose at low pressure. Water is mainly needed to wet your engine components so it can loosen dust and dirt, before the degreaser does its work, and finally rinsing parts off to reveal a clean engine bay.

Some professional detailers even use a pressurised steamer, because it is just as effective as a water jet but uses very little water. Instead, it shoots hot vapour in a controlled fashion in a small area. This is commonly used when cleaning the engine of classic and vintage vehicles, which are more sensitive to water.

After using water how do I dry my engine?

The first step is to wipe as much of your engine dry with a clean towel or microfiber cloth. Try to get as much moisture off at this time.

After which, if you do not have access to pressurised air, use a household leaf blower or even a hairdryer to dry off the hard to reach places, play special attention again to those electrical components and connectors.


Finally, let your engine sit for a while (circa 15-30 minutes) in the open so excess moisture can come out. Then start your engine for a minute or two and check if everything is ok. Once this is done, turn off the engine, and go in with a cloth to wipe off any excess water that may have been kicked up during the restart.

What if I drive an older car or a classic?

The same considerations apply even if you own an older car. In this case, be more careful with electrical components and collectors. In an older car, there is a chance that parts that seal off electrical items are loose and a bit less capable of protecting its components, other considerations might include the spark plug coils, fuse box, and ECU compartment.

In this case, try not to use water from a hose, a household spray bottle is better. 

How would I know when my engine is clean?

Well, you’ll know.

The main objective is the general cleanliness and presentation of your engine. With some time and effort spent, your engine will be looking miles better and will run smoother and better simply because it’s been rid of all the dirt, dust, and grime.


Depending on the age and mileage of your vehicle, it might be tough to get it looking like when it was new, but it will look very presentable.

How do I protect my engine components from dirt after a clean?

This is often overlooked, and very important.

The simplest way of protecting your engine is using an engine protectant spray or paste. Engine protectants cover plastic, rubber, and metal components and form a barrier so dust and grime do not settle onto those parts or components thereafter.


Please note that using non-specified products like tyre polish or very oily substances might make the parts look shiny but will attract more dust after, these protectant sprays are also formulated to handle the higher temperatures in an engine bay. Therefore, invest in a good engine protectant spray.

How often should I clean my engine?

Well, as often as you’d like.

If you clean your engine often enough, you would probably only have to use a damp cloth and a mild cleaning solution to leave your engine looking shiny and new, dirt and oil won't have time to get embedded onto components and surfaces so your job is made much easier.


Simply spray the cleaning solution where needed, like on the engine cover, plastics, or components and wipe off with a clean towel.  

Don't forget to catch the entire #KasiBikin series on Facebook to find out more on detailing your car.

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