Can You Clean Your Car Engine With WD40

You probably heard that some people use WD40 to clean their car engine and you wonder if WD40 will do damage to your car engine. Wonder no more.

You can clean your car engine with WD40 without damaging it. Cleaning your car engine will WD40 will protect the metal parts from rust. However, WD40 is an oil and it will attract dust.  Let me walk you through the whole process.

There are many ways you can clean your car engine. I would like to share my experience with you and tell you which ways actually work.

Cleaning Your Engine With WD40

You don’t have to be a mechanic to clean your engine with wd40. Make sure you follow my steps and you will have a shiny engine in no time.

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  1. Remove dust from electrical contacts: Use an old toothbrush which turns out pretty effective.
  2. Dust off remaining loose debris: Place plastic sheets under the car to catch any dirt/grime that drops.
  3. Start spraying your car engine with WD40.
  4. Avoid the electrical contacts: You may want to tape off the electrical contacts.
  5. Wait for at least 40 minutes so the WD40 will take effect.
  6. Use a brush to agitate the grease: Wipe off the dirt onto paper towels. Dispose of them correctly.
  7. This process will take 2 hours of your time.

I really enjoy cleaning my engine and giving it a nice shiny look. Here is how I clean my car engine:


The first step is the preparation. Although it seems simple, it’s important to have all your cleaning supplies laid out right next to your engine. That’s going to make it a lot quicker to clean the engine and lot more enjoyable because your products are going to be right there for you to use. It’s also a good idea to put on some gloves to protect your hands from chemicals and oils and put on some safety glasses just in case some dirt splashes in your face. You are ready to start.

Start off by isolating the power source which is the battery by disconnecting it and if your battery is easily removable, please do remove it because it will be easy to clean the area beneath the battery. But if you cannot remove the battery, make sure you disconnect the positive and negative leads and isolate them from the rest of the car. Everybody’s biggest concern when cleaning their engine bay is getting water in something that you shouldn’t and then it shorts out but with the battery completely disconnected there’s no electric running through any of this so you can’t short anything out. There’s a lot less to worry about and then when we’re done cleaning and detailing the engine we can make sure everything is dry and then reconnect the battery and we’ll be good to go.

Finally the last step of the preparation. Even though we disconnected the battery there are still some components that we don’t want to get wet. Sure you can get a little wet, but you don’t want to get them soaking wet for example. We have the alternator, distributor(some cars have two distributors). Follow your spark plug wires and press down the caps to make sure they are forced all the way down that helps keep water out. These components can get splashed with water, but the idea is we don’t want to soak them with water if we could help it.

Dry Clean

Next step is to dry clean the engine. Before we get the engine wet at all with the engine completely dry, we are going to clean it. Reason being is a lot of the dirt and debris that gets on the engine is just dust and road grime that settles on the top of everything, so before we get water on the engine bay and get it completely soaking wet and then that water pushes the dirt into places we can’t easily reach, we are going to clean it and to do that it’s really simple. We are going to be using brushes. First, since there’s going to be a lot of dust, get your dust masks on. It really doesn’t matter what brushes you use, I like to use brushes with a long handle so I can get into those hard-to-reach spaces. Also, it will be nice if you have a metal wire brush. So, you will use the brushes to agitate all the surface dust but how do you remove that? There’s a couple of ways and it depends what you have. I personally like using a vacuum. That way you could suck it up and also use it later to help dry the engine. If you don’t have a vacuum, then you can use something like a leaf blower.

Start by using the brush and vacuum cleaner together, and kinda throw the dust into the vacuum cleaner with the brush. You want to brush off as many surfaces in the engine bay as you can. This process is pretty quick and it only takes about five minutes and it’s definitely helpful. If you have any rust on your metal engine parts, you can use the metal wire brush and take the rust off. That’s all it takes to dry clean the engine.

Wet Clean

The step that gets everybody nervous is the wet cleaning step. This is where we take a hose and we wet down the engine bay. But you don’t have to worry, I will try to explain everything you need to know so you don’t damage your engine. This step is actually a lot easier than everyone makes it out to be.

Now a common question is should you clean the engine when it’s warm or cold and the answer to that is you could clean it when it’s warm or cold. If you’re going to clean a warm engine just put your hand on top of it and make sure you could comfortably keep it there. If it’s too hot, let the engine cool down. You don’t want to put cold water on a hot engine because it causes the metals to contract quickly which could wrap or crack engine parts. But a warm engine is better to clean on than a cold one because all the dirt and grime and grease comes off easier when it’s warmer.

First, you will have to clean the hood. Start off by covering your engine with a plastic bag. You do not want to get too much water on top of the engine. This goes for all engine types, the ones with and without the plastic cover. Spray your hood with water. Next get a degreaser and spray down the hood liner and painty surfaces. Now with a microfiber towel simply wipe down the painted surface and remove the dirt. Grease should come off pretty easily. Finally, rinse everything down with water and wash all the dirt away. Before we remove the plastic bag, you would want to clean the outside of the engine bay. So pick a side to start and work your way around the engine. Spray some soapy water and then grab a brush and wipe down every surface that you could reach. Finally, rinse the dirt away with a hose. Remove the plastic bag from the engine.

Now it’s time to deal with the engine. Split the engine down the middle and pick a side to start cleaning. The tricky part is that you cannot use a hose to rinse down the engine so we need to have good access to clean the engine. If your engine has a big air intake, and it’s in your way, just remove it. Disconnect the sensors and remove the hoses connected. If you don’t know how just leave it there and work your way around it. Start by cleaning any grease with a cleaning wipe. Removing thick grease areas will allow your engine to cool down faster because the grease acts as a layer of insulation between the engine and the cold air around it. Next, spray down the area with soapy water and use a brush to agitate all the dirty surfaces. For the areas that you cannot reach, use a pipe cleaner. Since there are a lot of electronics near the engine we cannot use a water hose. So instead we are going to use a microfiber towel and we’re going to wipe everything down. So now we have a nice clean engine. It’s time to move to the next step.

Drying The Engine

After cleaning the engine we’re left with a wet engine bay. So grab a microfiber towel and start drying everything down. This is actually a pretty important step. You want your engine to be completely dry before we move to the next step which is detailing. Make sure you leave no standing water. If you cannot reach the standing water parts, use a vacuum and suck the water out.

Detailing The Engine

And the final step is the detailing step. First, start by detailing all the rubber and plastic surfaces. In order to do that you will need a commercial product. Ultimate Black is a fine product and does a great job. Make sure you don’t apply any product on the belt as it may start to squeak. After you are done applying the product, leave your car to sit for 10 minutes. Get a microfiber towel and rub down every surface you applied the product on. That’s it.

Put back your battery and start your car.

Is your engine oil due for a change? Visit our Car Fluid Guide Website to learn the importance of changing your oil on time, which type of engine oil is best for your vehicle, and much more.

Car Care Hacks

Hi there. I am a certified Automotive Service Excellence (ASE) mechanic since 2018 and a car detailer for 10 years.

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