How to Clean the Engine Bay of Your Car [Safely]

Cleaning a Car Engine Bay

When it comes to cars, we tend to focus on the exterior of the vehicle because that is what catches our eye. Keeping it clean, applying wax, and taking all of the necessary steps to ensure that it is spotless can all be done relatively easily.

But an area that often gets forgotten about when it comes to the cleanliness factor is the engine bay. This seems silly when you think about it, because the engine bay houses some of the most important parts and pieces of your vehicle.

Keeping your engine clean can actually help it to cool more efficiently, and there will be less wear on things like pulleys and bearings. Having a clean engine bay can also help you single out leaks more effectively, and there will be less of a chance that dirty particulates get sucked into your filter.

The thing is that there is definitely a right way to do it, as you need to take care when dealing with any of the parts in your engine bay. Here is a helpful guide that will allow you to get into your engine bay easily and keep those essential parts as clean as possible.

​Tools and Accessories Needed

You’ll need a few tools to ensure that the cleaning process is done promptly, safely, and correctly. None of them are terribly rare, and there’s a good chance that you’ll have most of them around your house, although a few you’ll likely have to go out and buy.

Here is the list of tools that you will need to perform a safe, efficient engine bay cleaning:

  • Bucket
  • Water hose
  • Plastic bags
  • Absorbent pads
  • Drip pan
  • Car wash mitt
  • Car wash soap
  • Wash brush
  • Clean terry or microfiber towels
  • Engine degreaser
  • Plastic and metal cleaner/polish

Once you have these items in hand, you are ready to get moving down the path to having a cleaner engine bay than ever before.

Hose It Down

The first step in the process is to do this on a warm day. This is so the water can adequately evaporate, as you will be introducing it into areas where it may not be designed to go. This is why a quick dry-off time is essential. 

A pre-rinse does a few things for you. Primarily, it knocks any loose grit and dust out, making it much easier for the engine degreaser to spread around. It also helps to prevent spots should the soap dry out quickly. Do not skip the pre-rinse.

It is also important to note that your engine should be cool. Introducing water to hot parts can lead to steam, and that can be a nasty thing to get on your skin. Make certain to pop the hood and let it air out for around an hour or so. You can use this time to put down absorbent pads and drip pans to make sure that the chemicals and the debris from the engine bay don’t go down the gutters.

Before spraying, you will also want to make certain to disconnect the negative battery terminal, or at the very least, cover it with the aforementioned plastic bag. Water conducts electricity, and you definitely don’t want it to connect and wind up making new temporary circuits.

If you have a classic ride, make sure to cover the alternator, distributor, and carburettor with plastic bags. On newer cars, you’ll just need to cover the alternator and make certain to limit the amount of water that hits the coil packs and fuse box.

Spray the Bay

Once you have completed the aforementioned steps, it’s time to spray on a copious amount of engine degreaser. Degreaser here is better than car wash soap, because the latter will clean out dirt and grit, but it won’t cut through the grime and oil.

For nastier parts, make certain to go a little heavier on the degreaser, spraying quickly and thoroughly. This can include things like the oil pan, the starter, and anything else that may be particularly oily. Always consult the directions on the bottle, but you will generally need to let it sit for a few minutes to allow it to lift up the grime.

In the particularly filthy areas, use a brush with soft bristles that won’t scratch plastic or paint. This will ensure that all the grit and grime is removed from each of the parts. When you rinse the area, use a low-pressure water so you can see what kind of progress you are making.

For the metal parts, you can actually use something like an aluminium brush, as the surfaces are a little tougher and are able to withstand a little heavier hand. These include parts like the top of the intake manifold plenum and the heat shield. With the right cleaner and a little bit of elbow grease, you should start to see the dirt lift off right away. It is imperative that you don’t let the degreaser dry out, either.

Depending on the mileage, age, and condition of the bay, you may need to repeat the process a couple of times to ensure that all of the grease and grime has been removed. Once you have finished getting all the nastiness out, use the car wash soap to finish cleaning the engine bay just as you would the exterior of the vehicle.

For this, you can use the wash mitt. Get it soapy in the bucket and scrub down the engine bay just like you would a door or a quarter panel. Rinse when you’re done.

Be Thorough

When you’ve finished rinsing with low-pressure water again, you can remove the bags from the sensitive parts. If those parts need cleaning, it is important that you not do it yourself. Professional detailers can remove the plastic covers or caps and clean them by hand. This ensures that the electronics aren't affected.

You can also use a plastic cleaner or polish to get any fine scratches out and put a bit of shine back into your engine bay plastics. You can apply it with a terry cloth and then wipe it clean with the microfiber cloth to provide plastic that looks brand new.

For the metal parts of the engine bay, you will need a metal polish to brighten those up. Depending on the metal polish that you use, you might need to grind a bit into the metal surface, looking for the polish to start to turn a darker shade. When this happens, wipe it clean with a cloth and enjoy the shine.

It isn’t nearly as complicated as one might think to keep an engine bay clean. Aside from looking really nice, keeping the engine bay clean and free of debris can have many positive effects on the various components of your vehicle’s engine, helping them to run more efficiently for far longer.

In addition to these obvious benefits, there is nothing quite like looking under the hood of your car and seeing a nice, neat engine bay staring back at you. It will remind you of a job well done and that your engine bay is clean and protected from the grit and debris that plague so many cars.

Last Updated On: April 1, 2020.

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