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The Best Engine Degreasers and Cleaners 2021

best cleaning products for engine bay

The engine bay looks great when clean but they can become covered in grease, dirt, grime and debris that builds up quickly. By using a quality engine degreaser and cleaner, you are able to safely remove stubborn dirt under the hood without any adverse side effects.

The best engine degreaser is the Chemical Guys Signature Series, which is a professional strength citrus based formula for tackling tough grease, grime and dirt.

Using a regular car wash soap can remove some dirt from within the engine bay but may leave the plastics (such as engine covers) with water spots. Using engine degreasers remove the tougher dirt and leave no residue whatsoever.

Table of Contents

Engine Bay Cleaner Comparison

Engine CleanerTypeSize(s)
Chemical Guys Signature SeriesSpray4 - 128 oz
Meguiar's Super DegreaserSpray128 oz
POR-15 40101Spray128 oz
WD-40 Foaming SprayFoam18 oz
Gunk EB1CA OriginalFoam15 oz
Simple Green 19128Spray128 oz
Chemical Guys All CleanSpray16 - 128 oz
Griot's Garage 10959Spray22 oz
Adam's All PurposeSpray16 - 640 oz
Sonax 543200Spray16.9 oz

Taking your car detailing process to the next step with engine degreasers can make all the difference. Many people avoid this type of detailing as it can be fairly easy to damage an expensive component of the engine. However, with a proper engine bay cleaner and the correct process, you are able to achieve excellent results.

Regularly detailing your engine bay will not only make it look nicer but also reduce debris building up in any air intakes, which could cause issues.

Below is a list of the best engine degreasersthat make cleaning the engine bay more effective and safer than homemade solutions.

The Best Engine Degreaser

1. Chemical Guys Signature Series Orange Degreaser

At ProCarReviews, we are huge fans of the Chemical Guys detailing products as they provide great results each and every time. Unlike the brands “All Clean” alternative below, this formula provides additional cleaning power for tackling stubborn grease.

It’s a professional strength citrus based engine degreaser that can also be used upon tires, rims, undercarriages and much more.

Other features of the Chemical Guys Signature Series include:

  • Highly concentrated formula
  • Removes grease, grime, dirt and debris
  • Available in 4 oz, 6 oz and 1 gallon bottles
  • Distinctive orange coloring
  • Heavy duty cleaner

The Signature Series by the Chemical Guys brand is a powerful formula that emulsifies grease, grime and dirt. The main drawback is that it does come with a premium price but it’s backed by a reputable brand for peace of mind.

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2. Meguiar’s D10801 Super Degreaser

Meguiar’s are a highly reputable detailing brand and their “Super Degreaser” is an affordable and top rated engine cleaner. It’s a versatile formula that the brand claims can break down even the toughest of grease in a matter of minutes.

Unlike similar priced alternatives, this engine bay cleaner promises not to leave any white residue stains upon any surface under the hood.

Other features of the Meguiar’s Super Degreaser include:

  • Concentrated formula that can be diluted
  • Herbal fragrance solution
  • Residue free performance
  • Breaks down in the toughest of dirt
  • Suitable for multiple applications
  • Large 1 gallon bottle

This degreaser can be used for automotive exterior use only but cleaning an engine bay is what most people use it for. The industrial strength formula breaks down tough grease that has been under the hood for years with ease. It’s the best engine degreaser for the money and is backed by the reputable Meguiar’s brand.

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3. POR-15 40101 Engine Cleaner Degreaser

POR-15 are well-known for their rust prevention paint and this cleaner and degreaser formula follows their great reputation. It’s designed for use upon engines, fuel tanks, holding tanks, plastics, painted surfaces and much more.

It’s a water based formula that in non-flammable and completely safe to use upon the engine. The brand claim that it’s designed for professional use with great results.

Other features of the POR-15 40101 Cleaner Degreaser include:

  • Removes grease, oil stains and dirt
  • Available as a 1 gallon or 1 quart bottle
  • Suitable for multiple surfaces
  • Cleans and degreases
  • Concerntrated formula
  • Dilutes to suit your cleaning requirements
  • Water based formula

The POR-15 engine cleaner and degreaser is a highly effective formula that provides instant results. It’s worth noting that depending upon the dilution, it will produce fairly powerful fumes and it’s advised to use it in ventilated areas.

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4. WD-40 Foaming Engine Degreaser

WD40 isn’t the first brand you would think of for engine bay detailing but they have a dedicated degreaser. The normal WD40 formula is renowned for removing squeaking noises, lubricating components and much more but this product is specific for degreasing.

In order to clean the engine bay, it uses a low residue foaming formula, which is able to reach all the tight areas under the hood for a deep clean.

Other features of the WD-40 Engine Degreaser include:

  • Removes all types of dirt
  • Low residue foaming formula
  • Nozzle sprays up to 5 feet
  • Smart straw is included
  • Water based formula
  • 50 state VOC compliant
  • 18 oz bottle

As with any WD40 spray, there is a dedicated nozzle that you can use to target hard to reach spots within the engine. Even if it’s far away, the long distance spray pattern will be able to reach the targeted area. It’s an engine bay cleaner that provide superior accuracy, which is great for cramped engine bays.

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5. Gunk Foam Engine Bay Degreaser

Gunk have a range of products that deal with degreasing engine bays to garage floors. Their dedicated engine degreaser is a foam based formula that clings to dirt, dust and grime, which can then be rinsed clear with water.

In terms of using this engine cleaner, all that is required is to spray the dirty areas and then wait 10 to 15 minutes before hosing it down.

Other features of the Gunk Original Degreaser include:

  • Original formula that’s used by professionals
  • Foam application that clings to dirt
  • Removes grease and grime
  • 15 oz aerosol can
  • Industrial strength formula
  • Rinses clear with water
  • Requires no scrubbing

The brand also offer various other engine cleaner products that are suitable for specific types of dirt. They even offer an engine protector and shine formula, which enhances the overall appearance of the engine bay once completed.

Overall, it’s an excellent all-round engine degreaser that doesn’t require dilution and can be sprayed straight onto the engine. The foamy formula clings to all dirt and it requires no manual scrubbing to agitate the degreaser.

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6. Simple Green 19128 Crystal Engine Degreaser

Simple Green Crystal is one of the safest engine degreasers on the market. The formula is non toxic, non-hazardous, non flammable and non-corrosive. This provides peace of mind that you won’t cause any adverse effect whilst using it upon the engine.

Unlike other engine bay cleaner products, the Simple Green formula has no added colors and doesn’t have any fragrance, which may be a requirement for many people.

Other features of the Simple Green Crystal include:

  • Biodegradable
  • Fragrance free solution
  • Highly concentrated
  • No added coloring
  • Can be used on other parts
  • VOC compliant
  • 1 gallon bottle

As the Simple Green formula is highly concentrated, we recommend that you dilute it within a spray bottle. This makes the engine degreaser last far longer and adds extra bang for your buck. If you are worried about damaging the engine whilst cleaning, this is the best option. It’s completely safe to use and provides excellent results.

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7. Chemical Guys All Clean Engine Cleaner

Another engine cleaner product by the Chemical Guys brand is their All Clean formula. It’s one of their most popular engine cleaner formulas that cleans all dirt, grime and oil stains from the engine bay with very little effort.

It’s a natural cleaning formula that has a hint of citrus, which is designed to remove the dirt even faster than other cleaners.

Other features of the Chemical Guys All Clean include:

  • Advanced citrus based formula
  • Highly Concentrated and can be diluted
  • Produces a showroom finish
  • High quality 16 oz spray bottle
  • Suitable for other surfaces

It’s important to note that the Chemical Guys All Clean formula is more of an engine cleaner than degreaser. Although it will be able to remove grease, it will require scrubbing and may not be suitable for a large quantity of grease.

However, if you require it just for cleaning, it’s the best engine cleaner that can also be used on several other exterior surfaces.

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8. Griot’s Garage 10959 Engine Cleaner

The Griot’s Garage 10959 is a mild degreaser and engine cleaner that prepares the surface ready for dressing. It’s designed for light to medium layers of grease and safely removes dirt, debris and grime with ease.

In terms of using this engine cleaner, simply spray it onto the surface, agitate it with a detailing brush and then rinse it off with water.

Other features of the Griot’s Garage 10959 include:

  • Mild cleaner degreaser
  • High quality 22 oz spray bottle
  • No smell or residue
  • Bulk buy options available
  • 100% satisfaction guarantee

The Griot’s Garage 10959 formula loosens and breaks up dirt, grime and debris which can then be wiped clear to reveal a clean engine bay. The brand also offer an oil and grease cleaner, which has further degreasing power for more heavy duty cleaning.

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9. Adam’s Heavy Duty Engine Cleaner Degreaser

The Adam’s All Purpose Cleaner is a powerful option that is removes grease from the engine bay with ease. It uses advanced nano technology that is designed to lift the most stubborn of grease at a molecular level.

Depending upon its usage, this cleaner can be diluted to best suit the cleaning surface. If you are using it for tough grease, you will want to keep it concentrated but for sensitive surfaces, it can be diluted by up to 90%.

Other features of the Adam’s All Purpose Cleaner include:

  • Heavy duty engine degreaser
  • Diluted for cleaning purposes
  • 110% satisfaction guarantee
  • Available in 16 oz spray bottle or 1 and 5 gallon containers
  • Suitable for most automotive surfaces
  • Made in the USA

The Adam’s All Purpose Formula is an excellent all-round engine cleaner and degreaser that won’t disappoint. It’s also available in large containers, which allows you to refill the spray bottle for extra bang for your buck.

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10. Sonax 543200-755 Engine Cold Cleaner

The Sonax Engine Cold Cleaner is an affordable option that is phosphate and solvent-free. The brand state their formula will easily clean both oil stains or grease from the engine bay but also dirty assembly parts and tools.

In order to reach inaccessible areas of the engine bay, the formula has excellent infiltration abilities, which provides a deeper clean.

Other features of the Sonax Engine Cold Cleaner include:

  • Safe on all metal engine components, tubes and hoses
  • Lifts all oil and grease from the engine bay
  • Not suitable for use in direct sunlight or on hot engines
  • Requires 3 to 5 minutes of dwell time
  • 16.9 oz bottle size

Although it’s an affordable product, it cannot be diluted, which means that you may find yourself using a lot of the formula. However, it’s a powerful cleaner that is safe to use on all the engine bay metal components as well as the tubes and hoses.

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Engine Degreaser and Cleaner Buying Guide

Although the engine is tucked under the hood, it still becomes quite dirty overtime. The majority of car owners will not go near their engine at all but for those that are serious about detailing, it can be a rewarding job to accomplish. All the thick and tough dirt can be easily removed with a powerful engine degreaser that is effective at removing dirt and of course, being safe.

Cleaning your engine bay isn’t the most enjoyable job and therefore you will want it over and done with quickly. Using a simple soap or home remedy will usually require a fair amount of scrubbing and this is why you should stick to a degreaser or dedicated cleaner.

To help you make an informed buying decision, we have produced the below guide regarding engine degrease and cleaner products.

Engine Degreaser

How To Clean Engine Bay

Cleaning the engine bay require a delicate touch with many horror stories being told online. The potential to damage expensive electrical components can be quite daunting. You will often find people using their powerful pressure washers, which is fine when used correctly. However, many people misuse them, which can cause a damage to the wiring loom or sensors.

Below is the safest method of cleaning an engine bay:

  1. Prepare The Engine. With the engine cold, you will want to remove loose debris and cover electrical and delicate parts. These parts include air intakes, sensors, ignition wires and coils.
  2. Removed Baked Dirt. Due to the heat that an engine produces, the dirt can become “baked” on the engine. To remove this type of dirt, simply use a wired brush and remove the tough dirt.
  3. Apply Engine Degreaser. Using a recommended engine bay degreaser above, spray down the work area and let the product get to work by leaving it for at least 30 seconds. You will then need to use the wired brush again and work in the degreaser to tough dirt.
  4. Dry The Cleaner. After the scrubbing of the degreaser, use a microfiber towel to remove the solution on your engine bay. The engine bay should be clean and ready for additional detailing products if required. Ensure that there are no pools of degreaser under hidden compartments or wires.
  5. Increase Shine and Protect. It is the best time to add additional shine and protection to the engine bay once degreased. Using the recommended detailing products mentioned in this article, spray onto the microfiber towel (A new one) and rub onto the engine bay. Avoid spraying directly because this can leave abrasive markings.

If you were to use water based methods, you would use a pressure washer on the widest setting to spray away the degreaser. The most important thing to remember is not to spray over the covered areas because the plastic you used will simply split leaving it exposed.

Personally, there is no need to use water as you will get the same results with or without water. You are just adding additional risk to your engine bay. For a complete guide to engine bay cleaning, check out this detailed guide.

Engine Bay Cleaner

Types of Engine Degreaser

Not all engine degreasers are the same and some are petroleum based and others are water based. Petroleum engine degreasers have industrial strength and are often cheaper as it doesn’t use expensive ingredients within the formula.

The main drawback is the fact that its more abrasive, which means it should only be used on the specified surfaces. These will be stated on the product but it will more than likely say most plastics and other components.

Water based engine degreasers alternatives are mire safer to use and can usually be used on a range of surfaces. Therefore you do not need to worry about a small amount of overspray. The formula is far more advanced in order to make it a safe degreaser to use on cars but this does not mean its not as effective.

Engine Detailing

Once you have successfully used an engine degreaser on your engine, you can take things a few steps further. Many people will opt for an engine dressing formula to provide a sleek finish. Some car owners even use a tire shine as a dressing on their plastics under the hood.

However, be sure to check on the back of the product on whether it can be used as the engine will reach high temperatures. This will have the effect of heating the product up and turning it a different color.

Depending upon the age of the vehicle, you may even have faded plastics too. This can ruin the look of your engine bay but there are many different types of plastic restorer products that will return the fade to a more attractive black.


The engine bay can sometimes never be cleaned but for those that are serious about detailing, its a job worth doing. From simply using an engine degreaser to performing a complete engine detail to return it to factory condition.

There are various different methods of cleaning under the hood but using the best engine degreaser you can find is the safest option. Its simply not worth using a highly abrasive or powerful pressure washer on the engine as the damage when things go wrong can be expensive. There are industrial strength degreasers available that do the job far easier than you could do using a pressure washer.

procarreviews author

Written By Dan

About the Author

Dan is an automotive journalist and owner of over 10 cars ranging from supercars, tuned cars, classics and your good old beater cars. He always likes to get his hands dirty with nut and bolt restorations or detailing sessions using the best products on the market.

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