How Tos & Tutorials

How to Clean an Engine Bay Thoroughly

Is your 4×4 engine bay filled with oil and grease? There may be different ways of cleaning an engine bay, but are you doing it properly and rigorously?

In this article, we’ll give you a step-by-step guide on how you’re supposed to clean an engine bay, from removing basic grease to removing stubborn rust, without accidentally damaging any of its vital part. After all, one of the best ways to welcome the New Year is having a squeaky clean engine bay.


A typical engine has about 2,000 moving parts. When one gets dirty, it has a domino effect that can eventually contaminate the other parts. That’s why, keeping the engine bay clean is a must and the frequency of cleaning it mainly depends on your location:

  • Rural/city setting – twice a year (every 6 months)
  • Humid setting – every 3 months
  • Cold/snowy setting – every 2 months


road salt

Some common reasons why your engine bay gets dirty in the first place are:

  • Road salt
  • Dust particles
  • Fuel residue
  • Lack of oil change
  • Sludge or mud
  • Water residue


engine fire

A dirty engine bay can pose many risks that include a foul smell. The average car emits about 11,000 grams of carbon dioxide per day, and about 4.6 metric tons of the same gas in a year. With a dirty engine bay, this can be further increased which can cause some respiratory illnesses if left unchecked. Aside from this, it can also cause:

  • Engine fire
  • Oil leak
  • Coolant leak
  • Electrical malfunction


There’s no magic trick to easily clean an engine bay because it just all comes down to doing it systematically.

Prepare for Engine Bay Cleaning

engine bay cleaning tools

Preparing all your necessary cleaning materials may be a no-brainer task but there are still others who dive into the cleaning process with incomplete tools. By having everything you need next to your engine bay, you avoid the tiring risk of going back and forth looking for and retrieving your items. 

Another thing to remember is to always wear gloves when cleaning because doing so protects your hands from too much dirt, prevents hand sweat from seeping through the engine bay and helps you maintain proper grip.

It’s also a good idea to wear simple eye glasses to shield your eyes against dirt splatters. But if you want to make sure nothing gets into your eyes, ATV goggles are very useful too because they create a tightly enclosed space around your eyes, which stops dripping dirt from entering.

Don’t forget to disconnect your battery’s power as a manner of isolating your battery from the rest of the engine bay area. Through this, you won’t accidentally cause it to short, if water manages to get inside.

Bear in mind though, your battery’s only 1 part of the equation because there are other engine bay parts you should avoid getting totally wet. Sure, they can be drizzled or splashed with water, but they can’t be exposed in water for too long such as soaking or immersion because they can cause trouble on your battery. These include:

  • Alternator
  • Distributors (Especially the electronic ones)
  • Spark Plugs
  • Spark Plug Wells

If your engine bay has a plastic cover in some areas, it means it’s protecting sensitive areas that should NEVER have water contact. In this case, make sure there’s no way for water to get behind the covered parts to prevent malfunctions.

Dust Off the Engine Bay

dusty engine bay

This simply means removing dirt from the surface or external portion of the engine bay itself. This type of dirt is in the form of dust particles that normally accumulate on outer engine bay regions. That’s why putting on your face mask is important to avoid sneezing and coughing as a result of dust inhalation.

The reason for dusting off is you don’t want to move such dust from shallow places to hard-to-reach areas that can easily cause them to increase over time and clog your engine bay. Hence, it’s pretty obvious that a dirty engine bay can lead to poor fuel efficiency.

For this part, you need various brushes to sweep away the dust on specific parts of the engine bay. Take note, you may use any type of brush as you desire because there’s no general rule stating which ones you should use in particular. Furthermore, the brushing off task’s easy because it won’t take much of your time at only 5 minutes.

With this being said, choosing your brush comes down as a matter of preference and level of convenience.

Large Paint Brushis very useful for doing quick dusting off on big areas of the engine bay.

Toothbrushcan be used for dusting off thin, small portions of the engine bay.

Metal Wire Brush – is effective for displacing dirt on the metal engine bay parts like the intake which is commonly made from aluminum. Using it also makes the intake appear as good as new, but be careful not to damage small bits and pieces that go around it.

Here’s the thing, if the metal engine bay parts are small and hardly noticeable, you don’t need a metal wire brush to clean it. However, if the metal parts are big enough to attract attention, then you should use it.

In terms of getting rid of the dust, you may use an air nozzle that you can attach to an air compressor to remove the dust from tight, hard-to-reach engine bay spots.

Alternatively, you may use a leaf blower to sweep away dust using a strong amount of air, or you may use your reliable vacuum cleaner to also blow away dust by just turning it around.

Wash the Engine Bay

washing engine bay

This happens when you start using water through a hose to remove engine bay dust and grime. A lot of people get worried on this part thinking they might accidentally damage a valuable engine bay part.

Some of them are even wondering if engine bays should be cleaned in warm or cold condition. The truth is, you may clean them either way. Although if the engine’s really hot to the touch, you need to wait for quite some time for it to cool down a bit. This is because when cold water meets a hot engine, the 2 extremely opposing temperatures create cracks on the metal parts.

Even though it’s okay to clean a cold engine bay, it’s still easier to clean a warm engine bay than a cold one because dirt and grime are soft when heated, which makes them fast to remove.

When you begin washing the engine bay, don’t neglect the hood because cleaning it is as important as cleaning the former. After all, it’s your aim to make your whole engine bay holistically presentable as well.

But before doing it, cover all sensitive engine parts with a trash bag. This applies to all engines including those with plastic covers, to ensure they don’t get drenched in water during hood cleaning.  

If your hood liner’s crippling or sagging, don’t use water hose to wash off dirt because too much water pressure can aggravate its surface condition. Instead, a damp cloth should do the trick. If your hood liner is extremely filthy, spraying it with a carpet cleaner can soften clingy stains.

For the engine bay, start cleaning the exterior parts specifically the sides and work your way around it. Again, be very conscious of the water pressure that’s coming from the hose.

Use cleaning wipes to collect remaining dirt on easy-to-reach areas and brushes on tight spots. Then, put water and warm dish soap degreaser on them including the metal parts, and go back with the wiping or brushing until you reach the final, general washing procedure.

In terms of cleaning the engine itself, it can be difficult to do at a glance because it’s filled with hoses and wires of various sizes which gets in the way. So, you need to visually divide the engine in the middle from top to bottom and choose which side to clean first. Detailed instructions are found on Chris Fix’s Channel.

how to clean engine

Regarding the use of a degreaser, if you want to come up with your own solution, you should produce a balanced dilution ratio that’s neither too concentrated nor too mild. This ensures it can accurately remove dirt without damaging any surface. See some suggested dilution ratios per container below courtesy of

Degreaser Dilution Ratios

Container Type Ratio
Soak Tanks 1:10
Dip Tanks 1:10
Pressure Washers 1:20
Parts Washer 1:10
Vapor Degreasers 1:10 (Modified)
Steam Cleaners 1:50

Dry Off the Entire Engine Structure

dry engine

After the washing process is done, it’s time to dry the entire engine system. Thoroughly wipe all areas with a new microfiber towel. The reason for this is you don’t want to bring back some of the dirt that you removed through the used microfiber towel.

Doing this also matters because it lets you gather the remaining dirt that water and soap weren’t able to remove.

Moreover, it lets you get rid of water puddles which formed on the hollow spots of the engine bay. Remember, everything must be completely dry before you reconnect the battery to prevent any shorting issue.

If you’re having a problem removing them, use either a toothbrush wrapped in a microfiber towel or a vacuum cleaner to absorb them.

Detail the Engine Bay and Hood

how to detail engine bay

If you believe your hood liner should use a bit of a retouch because it has scratches and perhaps its color is faded, then you have to restore it.

To do this, remove your hood liner by unfastening its clips and spray a non-flammable black dye on it to produce a shiny, coated surface.

For the hood alone and the painted areas of your engine bay, using a spray wax is helpful because it not only brings them back close to their original color but also protects the paint itself from damage and further fading.

Never use WD40s or motor oil on plastic and rubber parts or anywhere the engine bay. This is because they gather dust and can damage them. Instead, go for a trim restore because it doesn’t absorb dust and preserves plastics as well as rubbers from the harsh elements.

However, you don’t have to put trim restore on every part of the engine bay. All it takes is placing a small amount of trim restore on a single plastic or rubber area and dip a paint brush in it. Then, you use the paint brush to apply it to the rest of the engine bay parts.

If you’re bothered by the rusted areas on your engine bay, all you need to do is use a metal wire brush to rub off the surfaces and cover them with a paint marker.

engine bay cleaning tips

Whether you’re a beginner or a pro, cleaning an engine bay can still be overwhelming. That’s why, it’s important to always know what you’re doing and even more valuable if you acquire extra tips along the way.

One of these extra tips include choosing the right weather condition to do an engine bay cleaning. If it’s sunny outside, you give in to the risk of exposing the engine bay to too much heat. In turn, your water, degreaser and other cleaning substances easily dry off and won’t be able to properly perform their intended functions.

Because of this, working in a cloudy environment is best so as you don’t compromise your cleaning products’ quality. More tips are found on Pan The Organizer.


Just so you won’t have trouble what tools to use during the cleaning process, here’s basically a recap of what you need:

  • Gloves
  • ATV goggles
  • Cleaning brush
  • Hose
  • Degreaser
  • Non-flammable back dye
  • Spray wax
  • Damp cloth
  • Microfiber towel


1. Why is it important to keep the engine bay clean?

  • It is important to keep the engine bay clean in order to prevent dirt and debris from entering the engine and causing damage.

2. Can some cleaning agents damage the engine bay?

  • Yes. If you are pressure washing the engine bay, be sure to use a low pressure setting to avoid damaging the engine.

3. Why do you need to wait for the engine bay to completely dry?

  • Once the engine bay is clean, it is important to dry it off completely to prevent rust and corrosion.


Cleaning an engine bay can be challenging. However, if you’re equipped with the correct items and tricks on how to do it, you’ll find it very rewarding. By cleaning your engine bay on a regular basis, you not only improve your 4×4’s performance but also extend its lifespan.

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