How to Use Engine Degreaser

May 28, 2023

Need that engine looking fresh? We tell you the right way to use engine degreaser to get your engine bay spotless.

There are lots of reasons you might want to clean your engine: to keep your show car looking fresh, to help make sure everything under there is working the way it should, and even to help find that oil leak, because it’s impossible to tell where it’s coming from when everything is covered in oil. Here’s how to use engine degreaser to make sure you get your engine bay spotless without causing any damage.

Person using a brush and soap to clean a car's engine

How to Apply Degreaser

Before spraying degreaser all over your engine bay, let things cool down. Spraying the foam onto a hot engine is a bad idea. Doing so can create hot steam that can burn you, evaporate the degreaser before it has a chance to work, or even cause a fire.

Step 1

Protect sensitive parts of your engine bay. An open fuse box or exposed cold air intake filter are two places you do not want to spray degreaser. The same goes for any cracked or exposed wiring (two things you should fix anyway). Go easy on parts like your alternator. You can cover any or all of these parts with a plastic bag.

Step 2

Spray on your engine degreaser. A foaming product makes it easier to see where you’ve sprayed the cleaner. Regardless of the type you use, make sure you cover every surface you want to clean.

Step 3

Parts Cleaning |BLet the degreaser work. Read the label for specifics, but you should usually let it sit for 10–15 minutes to really attack the grease. If there are some extra thick spots, you can use a stiff bristle brush to help break up the grease and let the degreaser do its job. Soak those spots again after a scrub.

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Step 4

Rinse. Unless you’re a pro, don’t use high pressure water on your engine bay. There are too many vital electronic components that could have water forced inside this way. Use your hose nozzle instead. And you should still avoid spraying too much water on parts like your alternator, fuse boxes, and ECU.

Step 5

Repeat, if necessary. Years of accumulated grease, grime, oil, and other contaminants can take a few tries to get rid of. Think of it like removing one layer at a time. Repeat steps 2, 3, and 4 until you’re happy with the results. Remember that even with the best engine degreaser, your old engine isn’t going to look brand new again.

Step 6

If you want to keep your engine looking grease-free, there are products to help you do exactly that. An engine shine and protectant product helps by leaving a protective layer on your engine bay. That way cleanup will be a snap next time around.

How to pick an Engine Degreaser

There are dozens of degreasers, so how do you pick the right one? If you’re going to be degreasing dozens of engine bays, you can look for the NAPA Bodypro brand degreaser. It’s available in one-gallon and five-gallon sizes, and even by the drum for really heavy use.

If you’re concerned about the environment and don’t want to use harmful chemicals, there are also green degreasers available made with eco-friendly biodegradable natural solvents.

Aerosol cans of engine degreasers are also an easy way to spray down your engine bay. But for larger jobs, you can buy liquid degreasers and then apply them with a handheld sprayer. That makes covering it quick and easy to cover a wide surface area.