How to Clean Your Car's Engine (2024)

Don't you feel good when your car is clean and all shined up? A well-kept car looks great rolling down the street or sitting in your driveway, and you'd swear it even drives better. But if you want to take your ride all the way to beautiful, you also should to address the dirt and grime under the hood. Even though the engine bay is not exposed to the elements—at least not from above—debris and dust creep in from openings around the hood and the vehicle's front end. Cleaning your engine might sound daunting—how do you wash a big hunk of metal and plastic?—but following these 10 steps can turn the job into a simple afternoon task, and a very satisfying one. Here's how to clean your engine quickly and efficiently.

Step 1: Schedule

Ideally, pick a warm day. Warmer weather, especially low humidity with some wind, will help dry the engine and components after cleaning.

Step 2: Cool

If the car was running, flip the hood up and allow the engine to cool for at least 15 minutes. Hot engine components can not only burn you, but they can also be damaged by rapid contraction if sprayed with cool water.

Step 3: Remove

Remove any plastic covers under the hood. These can be scrubbed separately. Also remove the negative terminal from the battery. This will help protect the electrical components from getting damaged if they get wet. You can also remove the battery if you’d prefer, but we've cleaned many an engine bay without doing so.

Step 4: Cover

Using plastic bags, cover any sensitive electrical components, such as the battery, ignition wires, and engine control unit. If there's an exposed engine air intake under the hood, you'll want to cover that as well. If you feel like you'll be particularly careful with your rinsing, then you can skip this step. However, protecting these electronics will allow you to clean more thoroughly with less risk of damaging anything.

Step 5: Degrease

Thoroughly spray the entire engine compartment with degreaser. Any household degreaser will work, whether it's a kitchen cleaner or a purpose-made engine degreaser. We've used Simple Green (we like its eco-friendly formula). Don’t hold back—every square inch should be covered.

Step 6: Scrub

Depending on how dirty your engine is, you may not need to scrub. However, some areas, like the valve cover, may have years of caked-on oil and dirt. A small brush with synthetic—not metallic—bristles will go a long way toward working the degreaser in and cleaning away the gunk. Add more degreaser if needed.

Step 7: Rinse

If you have a power washer, you can use it on a light setting, but a standard hose will work as well. Or you can use the sprayer at the local DIY carwash. Rinse the entire compartment, working from back to front, washing away all degreaser. Try not to directly spray electrical components, and try to prevent spraying much water into areas that won’t dry easily.

Step 8: Dry

If you have compressed air available to you, you can blast air in the nooks and crannies to remove excess water. If not, wipe everything you can reach with a shop towel or rag. This will not only remove water but will also help remove any remaining grime.

Step 9: Replace

Reinstall the negative terminal on the battery and remove the bags covering the electrical components.

Step 10: Repeat

The key to making this project simple is not letting your engine compartment get too dirty in the first place. A quick degreasing every year or two will help keep your engine looking clean with no more than an hour of work. Your ride's engine may never look as sexy as the one above, but a gleaming engine bay is guaranteed to make you feel happy.