The Best Degreasers for Cleaning & Detailing Your Engine Bay

If this is your first time reading up about the touchy subject of engine bay cleaning, buckle up! We’re about to bust some myths and recommend some of the best engine bay degreaser options on the market.

There’s nothing sexier than a squeaky clean engine bay. But more importantly, spending all that time up close with your car will bring to light issues such as oil leaks or damaged car parts.

Even though you’re probably not looking at serious problems, it’s always a good idea to rid your engine bay of anything that doesn’t belong there, like dust, grime, grease and unwanted fluid residue.

So if it’s been a while since your car has had a good detail, or if it’s been sitting without being driven for some time, it’s time to give it the love it deserves. In this guide, we’ll take you through the proper way to clean your engine bay, and we’ll list some of the best engine degreasers that you can buy right now.

Greasy hands from changing a spark plug
If your hands look like this after simply changing a spark plug, it’s time to degrease your engine bay!

The Best Engine Degreasers You Can Buy

If you’re just here for answers, let’s jump right into it! All of the products that you’ll find on this list will do a great job. That said, there are a few that stand out and are the ideal products for their respective use cases.

Best Clean for the Money: 3D Grand Blast

3D Grand Blast Heavy-Duty Degreaser

3D has done a great job with this product. In terms of pricing and effectiveness, this is probably the best degreaser we’ve come across. In its concentrated form, it works well for heavy-duty applications, but you can also dilute it to 10:1 for light cleaning.

If You’re On a Budget: WD-40

WD-40 Cleaner Degreaser

WD-40 has been a staple name in the repairs and maintenance industry worldwide. It’s no surprise that their highly effective, yet affordable industrial-strength degreaser works wonders.

What’s more, is that it’s extremely affordable and you can always buy in bulk to save more.

For the Most Detailed Clean: Gunk Engine Brite

Gunk Engine Brite Gel

If you want a product that can get into every nook and cranny of your engine bay, you need one that has an aerosol trigger. Gunk Engine Brite is specially designed for older engines and works extremely well for removing caked-up grease that’s has been sitting for ages.

Want more info? Read on! We’ve scoured the market and found some of the absolute best engine bay cleaning products for you. Each of them are inexpensive and readily available.

Chemical Guys Orange Degreaser

Chemical Guys Orange Degreaser

Manufacturer: Chemical Guys
Part Number: CLD_201_16
Item Volume: 16 ounces
Buy On: Amazon

The great thing about the Orange Degreaser is that you can use it not only on engines but also on machinery, tools, and tires.

Chemical Guys use a citrus-based formula that works really well and emulsifies all kinds of grease, oil, and dirt with ease. You can prolong the use of the product by diluting up to 20:1 for lighter cleaning jobs.

It’s slightly pricey compared to others in this round up, especially considering that you only get 16-ounces, but it works like a charm.

WD-40 Specialist Cleaner & Degreaser

WD-40 Specialist Cleaner & Degreaser

Manufacturer: WD-40
Part Number: 300349
Item Volume: 24 ounces
Buy On: Amazon

The multi-surface degreaser by WD-40 is biodegradable and has a non-aerosol trigger. You’ll find that it’s easy to use because of the durable, shatter-resistance trigger and the convenient refill port.

You can use this product on glass and different metals like copper, aluminum, and stainless steel without worrying about etching or corrosion.

If you do happen to get some oil on glass, you can use this product without worrying about any damage. Metal, copper, and aluminum won’t corrode or rust either.

Besides being non-corrosive, WD-40’s degreaser is also non-flammable, non-abrasive, and has an inoffensive odor. But the best part of this product is its affordable price tag.

3D Grand Blast

3D Grand Blast Heavy Duty Degreaser

Manufacturer: 3D Car Care Products
Part Number: ‎100G01
Item Volume: 128 ounces
Buy On: Amazon

3D Grand Blast is a heavy-duty degreaser that you can use on engines, machinery, and tools. One thing we really like about this product is that it uses no-harm Prop 65 approved ingredients, making it eco-friendly.

You’ll find that it loosens up grime and grease surprisingly quickly. It’s also safe to use and easy to rinse on painted surfaces.

Even though it’s a heavy-duty degreaser, you can dilute it 10:1 for light cleaning. Otherwise, we recommend opting for a 4:1 dilution if you need to do heavy cleaning.

Gunk Heavy Duty Gel

Gunk Heavy Duty Gel Degreaser

Manufacturer: Gunk
Part Number: EBGEL
Item Volume: 15 ounces
Buy On: Amazon

If you’ve got an older car, the Gunk heavy-duty gel is perfect for you. Older cars tend to have a ton of grease and grime baked onto the engine surface, and this is just the product you need for an application like that.

Engine Brite doesn’t run off and drip everywhere — it stays on when you spray it, giving it enough time to penetrate through even the toughest engine soils. This is thanks to Gunk’s ‘rheological’ additives that allow the product to cling to vertical surfaces.

If you’re concerned about Volatile Organic Compounds, this product meets all state requirements with contents under 35%. What’s not to love?

Adam’s All-Purpose Cleaner

Adam’s All-Purpose Cleaner

Manufacturer: Adam’s Polishes
Part Number: 810004211131
Item Volume: 16 ounces
Buy On: Amazon

Adam’s All-Purpose Cleaner is a heavy-duty degreaser that works well to remove even the toughest grease and grime. For more delicate applications, Adam’s Cleaner can be diluted up to 90% with water.

Using this product with a brush is recommended. After application, you can use a strong water blast to rinse away grease.

If all of the grime doesn’t come out in the first wash, you can repeat the cleaning process to get optimal results.

Oil Eater

Oil Eater Cleaner & Degreaser

Manufacturer: Oil Eater
Part Number: AOD1G35437
Item Volume: 128 ounces
Buy On: Amazon

Oil Eater not only works well to remove engine oil, but aggressively removes grease and other substances that clings to your engine. Despite being so effective, Oil Eater is very safe to use. It doesn’t contain petroleum or abrasive solvents and is 100% water-based, meaning it’s also biodegradable.

You don’t have to worry about it damaging your engine parts as it is non-corrosive and non-hazardous since it’s USDA approved.

To get rid of grime that has built up over long periods, use it as a heavy-duty cleaner by limiting the water mix. On lighter surfaces, you can mix more water to make the product last longer without compromising how well it works.

Meguiar’s Super Degreaser

Meguiar’s Detailer Super Degreaser

Manufacturer: Meguiar’s
Part Number: D10801
Item Volume: 128 ounces
Buy On: Amazon

Although Meguiar’s degreaser works well to remove grease quickly and with minimal effort, you don’t have to worry about damaging any of your parts or components.

For use on lighter surfaces, you can dilute it to a solution of 10:1, and it will work just as well. Not only does it work hard, but it’s also residue-free. The free-rinsing formula of this degreaser helps to prevent white residue stains.

Because it’s effective, it’s very simple to use. All you do is spray it on and wipe away the grease and grime. No hard scrubbing is necessary.

Super Clean Tough Task Cleaner

Super Clean's Aerosol Degreaser

Manufacturer: Super Clean
Part Number: 309017
Item Volume: 17.5 ounces
Buy On: Amazon

If your engine has dirt and grime baked on metal surfaces, Super Clean’s Tough Task Cleaner is the ideal product. Like others, this is an aerosol spray degreaser that can directly target the spots with grease and grime build-up while avoiding the mess.

This is a highly effective product that cleans easily, so you can put in minimal effort and time while still getting a deep clean. It’s also safe to use as it is biodegradable and phosphate-free.

Because you can direct the application to the exact spots, you don’t have to worry about damaging your engine intake or other parts. The high-pressure stream works well to remove dirt from recesses and corners.

Sonax Engine Cleaner

Sonax Engine Cleaner

Manufacturer: Sonax
Part Number: 543200-755
Item Volume: 17 ounces
Buy On: Amazon

Sonax has manufactured the perfect engine degreaser that helps to remove tough oil and grease stains, even through mud. It also works just as well on vertical surfaces as it does hard-to-reach spots.

It is able to remove the toughest engine gunk quickly and effectively, but it’s also safe to use since it’s phosphate and solvent-free.

After you’ve sprayed on Sonax, wait for 3 to 5 minutes for it to seep into the grease, then rinse it off with a strong water blast. Remember not to use the product in direct sunlight or hot surfaces though.

Spray Nine Grez-Off

Spray Nine Grez-Off Degreaser

Manufacturer: Spray Nine
Part Number: 22732
Item Volume: 32 ounces
Buy On: Amazon

Spray Nine has produced a heavy-duty degreaser that is non-flammable, non-acidic, and biodegradable. It doesn’t contain petroleum solvents or unpleasant odors either.

You can count on Grez-Off to provide a quick and effective solution to your greasy engine bay gunk, but it also works on tools, garage walls, and other electrical appliances.

Spray Nine is a water-based cleaner that is USDA approved. This means it may require some scrubbing to get the really stubborn grease out. After you’ve applied the product, wait up to 15 minutes for it to settle into the dirt before you rinse. If you’re unsatisfied with the results after the first application, repeat the process.

Engine Bay Detailing — Frequently Asked Questions

The reason we called engine bay detailing a touchy subject is that there’s a lot of misinformation out there. There are many ways to do it right and many ways to do it wrong.

The cleaning method you choose comes down to what car you drive. The end result should be a clean engine bay without any damage to the engine, or any electrical components.

Below are some common questions that people ask about engine cleaning and the products associated with it.

Is It Safe To Spray Water Into My Engine Bay?

Whether you should do this or not largely depends on what car you drive. Unlike old cars, almost all modern cars have protected air boxes and weather-proof wiring connectors. Automakers do their best to design engine bays that are sealed off from the elements.

That said, don’t spray 2500 psi of water an inch away from your alternator. We do not recommend using a pressure washer to clean your engine bay. If you must use one, make sure to keep it on a low setting and maintain adequate distance from the engine while spraying.

Unsafe spraying of water at the engine using a high pressure hose.
Don’t be this guy.

On that note, if you have a garden hose lying around, use that instead — the pressure from one of those is usually sufficient and won’t damage critical components.

What Type of Engines Are Prone to Water Damage?

Automakers do all they can to keep their engine bays weatherproof. But, there’s only so much they can do. While most modern cars get away with this, there are two types of cars that you should be extra careful with:

Old cars are an easy target for water damage because even though they once had weatherproof engine bays, they may not anymore. Years of high temperatures and exposure to oils can take their toll on whatever little water protection these cars came with.

Plastics and rubber tend to get brittle and are prone to cracking in places you can’t see.

Modified cars, on the other hand, have a different set of problems. Weather protection depends on your specific setup. Most aftermarket part manufacturers aren’t concerned with making performance parts as waterproof or practical as OEM parts — that’s part of the appeal.

So if your car has an aftermarket air intake, forced induction, or a custom wiring harness, go easy on the water.

Exposed turbocharger in a modified BMW's engine bay
It goes without saying, if your modified car has an exposed turbocharger, spraying water in your engine bay is a recipe for disaster.

What Parts of My Engine Bay Should I Cover Before Spraying Water?

The best thing you can do is cover your entire engine when spraying water into the engine bay. Clean everything that’s around the engine following the steps that we’ll mention further below.

To clean the engine itself, you can spray a fine mist of degreaser followed by brushing and wiping off with a microfibre cloth.

Before spraying any water into your engine bay, it’s a good idea to cover the:

  • alternator,
  • sensors,
  • distributor,
  • crankcase openings,
  • oil dipstick
  • fuse box, and
  • any exposed electricals.
Protecting engine components when cleaning an engine bay

These parts can be covered with a plastic drop cloth. Even thick garbage bags will do the trick. It’s not just the electricals that you need to protect, you want to prevent any water from getting into the engine too.

Are There Any Mechanical Benefits to Cleaning an Engine Bay?

While there are no mechanical benefits to keeping your engine bay clean, it’s worth mentioning that keeping your engine bay clean might help prevent mechanical problems. When you’re elbow-deep under the hood, it’s easier to spot any leaks or issues when they start.

It is true that grease and dirt accumulated on top of your engine can trap some heat, but not to a point where it’ll make your car run hotter than normal.

There’s no evidence that a cleaner engine will run better than a dirty engine. However, a cleaner car will operate better as opposed to a filthy car.

Removing debris, twigs, and leaves won’t hurt. For example, if you let enough gunk pile up at the bottom of your windshield, your heating, ventilation, and air conditioning system might suffer.

Engine Bay Cleaning — The Process

Below you’ll find step-by-step instructions on how to clean your engine bay. Before you begin, take a look at some of the cleaning supplies you’ll need to get started:

If you’re really going all out, you might also want to use a wire brush attachment in a power drill too.

Here’s how it’s done.

Preparation

Start by making sure that your engine is at the right temperature. Working on a cold engine is recommended by most degreaser manufacturers, but there are advantages to working on a warm engine too.

If your engine is warm, it will help to emulsify the oil and grease, making it easier to remove. Know the difference between warm and hot — if it’s hot to the touch and you have to think twice before placing your hand on it, wait till it gets a little cooler.

If you live in a cold environment, avoid spraying cold water on a hot engine as the metal could contract and crack.

The next step is to disconnect your battery. You can either disconnect only the negative terminal, or you can remove the battery completely. The latter is what we recommend as it frees up more space for you to work around.

Then you want to take a note of where your alternator, distributor, and spark plugs are located. Make sure all connections are nice and tight. Remember that these parts of your engine bay will be covered with plastic right before the wet clean step.

Make sure that you take your time to do the prep work properly as it will save you headaches later in the process. If you have a removable hood liner, we recommend removing it because you can wash it separately.

Dry Clean and Wipe

Dry wiping engine

Dry cleaning your engine will make it easier for you to achieve the result you’re after, without having to spray a lot of water into the engine bay.

If you drive a modern car with exceptional weather protection under the hood, you may skip this step entirely unless you park in an area with trees or that is particularly windy.

Start off by removing as much of the dust as possible using only a set of synthetic brushes, a vacuum cleaner, and a microfibre cloth. It’s a good idea to clean off this dirt before the water pushes it into places that are hard to reach.

The idea is to eventually use as little water in the wet cleaning process as possible.

Wet Wash

This is the step that gets everybody nervous. Start by covering the top of your engine with a plastic sheet. Proceed to gently spray water with a garden hose all around the engine.

You can clean the engine separately using a degreaser, brushes, and a microfibre cloth, without spraying any water directly on it. As we mentioned before, this step will depend on what type of car you drive.

Degrease

The next step is to spray the affected area of the engine bay with a degreaser of your choice. Be sure to not spray any of the belts. Let it sit for 3 to 5 minutes so that dirt and grime can loosen up. If the dirt built-up is severe, you can use a brush or a rag to agitate it.

If you find that you’re dealing with oil leaks, you might want to repeat this step using a full-strength degreaser after rinsing off.

Scrub

Once you’ve let the degreaser sit for a while, scrub down the most affected parts of your engine bay with a suitable brush or wash mitt. This will make it easier for you to get rid of the dirt without using too much water.

Areas such as the valve cover might have years of dirt and oil built up. So scrubbing that area is necessary. Make sure to use a brush that has synthetic bristles, not the metallic kind.

Rinse

After you’ve applied degreaser and scrubbed off the dirt, it’s time to rinse away all of the debris. If you’re using a power washer, make sure to keep it on the low setting. A regular hose is better suited for the job.

Rinsing engine degreaser with a water hose

Air Dry

To dry the engine bay up, you can either use an air blower or simply wipe it down thoroughly. If you see puddled-up water anywhere in the engine, use a vacuum to get rid of it.

Finishing Touches

Once the engine bay is dry, you can reinstall the battery. To really make things pop, you can finish off with polishing the painted surfaces and painted surfaces with a water-based trim restorer.

Using trim restorer on engine bay

This non-greasy solution will rejuvenate the deep black color of the rubber and plastic components in your engine bay.

Like New From the Production Line

We’ve listed the best engine bay cleaners and the ones that we think will be the most beneficial to you, but there are plenty more out there.

Which degreaser do you like to use for cleaning under the hood? Did we miss one that should be on this list? Let us know in the comments below!

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