How to Clean the Engine Bay of Your Car

When it’s time to top up your oil and fill up the screen wash, how good will it feel to pop open the bonnet and see a nice and tidy engine bay? No oil spills, no splashes and no mucky marks. Maintaining a clean engine will help prevent it from rusting and allow for inlets, outlets and passageways from becoming clogged with dirt and debris; keeping your engine performing better and lasting longer. Not only that, a clean bonnet will show that you’ve looked after your car, so it’ll add value to it if you’re wanting to sell it.

So, if you:

Want to add value to your vehicle;
Want to keep your vehicle in immaculate condition;
Want to know the steps to do it yourself;

Then, keep reading…

Things that you need to clean an engine bay

Not all car engines look the same, but the tools we need to clean them are fairly generic. They’re affordable too and can be found in most high-street DIY stores. Here are the products we recommend getting:

Microfiber cloths
Brushes – metal wire brush or toothbrush
Wet wipes
Pipe cleaners
Degreaser
Absorbent pads
Electrical tape
Pressure washer or garden hose
Face mask
Safety glasses
Rubber or nitrile gloves
Spray bottle
Plastic bags
Air blower or compressor (optional)

Risks and hazards when cleaning your engine bay

When it comes to cleaning under the bonnet and extending the life of your engine, it’s not as simple as splashing water and spraying cleaning products around. From letting your engine cool to protect the electrical systems, there are many steps to take to help you stay safe and keep your car protected when cleaning the engine bay.

First of all, pick a warm day to clean your car engine bay – it’ll help dry your engine and everything else once you’ve cleaned it.
Let the car cool down – if your car has been running, open the bonnet and let it cool down. Hot engine parts can burn your hands and they can become damaged if sprayed with cold water.
Tighten caps and covers – when you’re cleaning your car, you don’t want water leaking into caps that aren’t closed properly.
Protect the electrical systems – water and electricity don’t mix, so it’s best to disconnect the battery terminals and remove the battery if possible. Use electrical tape to securely cover the electrical parts like the alternator, fuse box, distributor cap and spark plugs.
Get all the protective gear – it’s best to protect your hands, eyes and mouth from debris and dirt and harsh cleaners.

How to clean your engine bay

Although you’ve had to wait for the engine to cool down, it’s actually best if the engine is slightly warm, as the grime will clean off easier. If you can comfortably put your hand on the engine for 10 seconds, then it’s good to begin. Don’t forget, it’s never a good idea to put cool water on a hot engine as the change in temperature can cause parts to crack. Now you can start the clean…

Remove the battery and protect electrical components:
As mentioned in the previous section, it’s best to remove the car battery and cover the electrical components like the alternator, distributor and spark plugs. The engine will need protection too. This can simply be done with a plastic bag and electrical tape. Don’t forget to tighten those caps and covers and cover any electrical sockets just in case.
Dry-clean all surfaces:
Now everything’s protected, use a brush to gently dislodge dirt and debris. Use a vacuum to suck it all up or a leaf blower to get rid of it all. If the intake needs cleaning, use a wire brush for that stubborn grime.
Spray down the dirt deposits:
Mix up a soapy water solution using warm water. Pop it into a spray bottle and moisten all exposed surfaces in the engine bay. The warm water will help prevent warm engine parts from cracking. Make sure not to spray the insulation blanket underneath the hood, as getting it wet can cause damage.
Prepare the area underneath the car:
Pop down absorbent covers on the ground under the engine and next to your car. It can help prevent toxic liquids from running into drains or soil nearby.
Degrease:
Apply a degreaser over the parts you’ve just sprayed with warm, soapy water. Pay more attention to where the grime has built up. Leave for 10 minutes.
Get scrubbing:
Use a microfibre cloth to remove the degreaser and loosened dirt on the easily accessible parts of the engine bay. And for those hard-to-reach places, use a brush. It’s much more eco-friendly to use a brush and reusable cloths instead of throw-away wipes that can only be used once.
Rinse thoroughly:
Now, take your hose and wash down the inside of the bonnet and the outside of your engine bay. Make sure your hose is on a low-pressure setting and try to avoid the parts of your engine that are covered up with electrical tape and plastic bags.
Clean the engine:
Use cloths to clean away the grease and oil. You can use a brush and degreaser for those stubborn marks. A toothbrush might work for those hard-to-reach places. Dry the engine off with a microfibre cloth – they’re great for soaking up water. Remember not to use the pressure washer or hose on high setting on your engine as the high-pressure water might damage it.
Dry your engine bay:
Now your engine bay is all clean, use a clean microfibre cloth to soak up any moisture. You could also use an air compressor or leaf blower to get to those areas your cloth can’t. It’s now time to take off that electrical tape, too.
It’s all in the detail:
Now your engine bay is all clean, it’s time to get it looking as fresh as possible. Use a fabric dye to correct any discolouration of the bonnet liner and then use spray wax for cleaning. Those plastic and rubber surfaces can be brought back to their former glory with a water-based trim restorer; it’ll make them shine and protect them from deterioration too. If you have faded lettering on your engine parts, bring them back to life with a colour-matched paint marker.
Put it all back:
Pop your car battery back in, take a step back and admire all your hard work!

Extra tips from the pros

Now your engine is all sparkling, I think we can all agree that a clean engine is a better engine. Not only will it take years off its age, but it’ll also help maintain your motor. Here are some extras to think about:

Clean your engine bay regularly

If left for a long time, grime and dirt can build up in your engine bay. That’s why it’s best to clean it regularly so you won’t have such a big job to do next time. Little and often is the way!

Start the engine

After you finish with the cleaning and you have dried the bay as much as you can, start your engine and let the increasing temperature clear the remaining moisture.

Pick a nice day

If you’re working outside in the open air, it’s important you pick a dry day. It’s best if it’s sunny too to allow for water to dry quicker.