Best Engine Degreaser For Pressure Washer: 10 Options Compared

#1 · Best Overall

1. Simple Green Pro HD

• Volume: 160 fluid oz
• Material Features: Biodegradable
• Form: Spray

Best for: Professional pressure-washing concentrate.

Why it ranks #1: Its listed applications include pressure washing and automotive cleaning, while the concentrated kit includes a 32-ounce spray and one-gallon refill.

Simple Green Pro HD explicitly lists pressure washing among its applications, giving buyers a direct match for equipment-based cleaning. The concentrated cleaner also comes with a 32-ounce spray and a one-gallon concentrate refill, supporting both ready-to-apply spot work and preparation of a larger cleaning supply.

Pro HD targets grease, grime, and stains on automotive and recreational vehicles as well as industrial equipment, connecting its pressure-washing use to engine and equipment maintenance. The concentrate refill supports preparing solution for broader jobs, while the included spray offers a separate way to address localized messes. Its professional-grade, non-corrosive description adds relevant context for multi-purpose work. The listed safety information warns of eye irritation, so protective handling matters during application and dilution.

Skip it if you want a low-odor cleaner; Simple Green Industrial Cleaner and Degreaser lists low odor as a feature.

Choose Pro HD if you want a pressure-washer-listed concentrate for automotive and equipment grime, with a spray for localized jobs. Its eye-irritation warning calls for careful handling during mixing and use.

Listed on Amazon as: Simple Green Pro HD Purple Concentrated Cleaner & Degreaser – Heavy Duty, Professional, Automotive, Restaurant, Grills, Ovens (32 oz Spray @Heavy Strength and 1 Gal Concentrate Refill)

#2

2. Oil Eater Original 1 Gallon

• Volume: 1 gallons
• Material Features: Biodegradable
• Form: Liquid

Best for: Pressure-washer dilution versatility.

Why it ranks #2: Verified facts specifically name pressure washers and engine degreasing; its one-gallon concentrated, biodegradable formula suits broader cleaning tasks.

Oil Eater Original is explicitly listed for pressure washers, parts washers, and equipment, enabling a concentrated gallon to serve several degreasing workflows. Its biodegradable, noncorrosive formula is also specified for washable surfaces, from engines and tools to concrete, making it a flexible option for garage and outdoor cleanup.

The concentrate can be used for engines, parts, tools, grease stains, and spills, so a buyer can carry the same cleaner from vehicle maintenance to surrounding cleanup. Its listed pressure-washer compatibility supports equipment application, while the one-gallon volume gives a supply for repeated work. The product directions emphasize using it on cool surfaces and adjusting dilution for surface porosity; that makes surface assessment part of the preparation routine before washing.

Skip it if you need a five-gallon supply; Oil Eater Original 5 Gallon offers the larger listed container.

Oil Eater Original fits users wanting a pressure-washer-compatible concentrate for engines, parts, and nearby oil stains. Follow its cool-surface and dilution guidance, especially when moving between porous and less porous materials.

Listed on Amazon as: Oil Eater Original 1 Gallon Cleaner, Degreaser – Dissolve Grease Oil and Heavy-Duty Stains – Professional Strength

#3 · Best Bulk Option

3. Oil Eater Original 5 Gallon

• Volume: 5 gallons
• Material Features: Biodegradable
• Form: Liquid

Best for: Bulk pressure-washer supply.

Why it ranks #3: The five-gallon concentrate is specifically listed for pressure washers and engine degreasing, making it suited to high-volume cleaning needs.

Oil Eater Original comes as a concentrated five-gallon supply and is explicitly listed for pressure washers, enabling buyers to prepare cleaner for repeated equipment use. Its stated applications span engines, tools, parts, grease spills, and oil stains on concrete, supporting work across a garage or service area.

The five-gallon volume suits ongoing cleaning where a smaller container would require more frequent replenishment, and the concentrate can be used in pressure washers, equipment, and parts washers. Its listed targets include engines and tools as well as grease stains and spills, letting users cover both equipment and surrounding surfaces. The biodegradable feature and non-abrasive specification add useful product context. Safety information cautions against use on hot or warm aluminum, glass, leather, silk, and suede.

Skip it if you need a one-gallon container for smaller jobs; Oil Eater Original 1 Gallon has the same listed pressure-washer use.

Choose this Oil Eater for recurring pressure-washer and parts-washer work that benefits from a five-gallon concentrate supply. Respect its material warning, particularly around hot or warm aluminum and delicate surfaces.

Listed on Amazon as: Oil Eater AOD5G35438 Original 5 Gallon Cleaner/Degreaser, light yellow, 640 Fl Oz (Pack of 1)

#4

4. Simple Green Industrial Cleaner

• Volume: 1 gallons
• Material Features: Biodegradable
• Form: Liquid

Best for: Low-odor concentrated cleaner.

Why it ranks #4: This concentrated, biodegradable gallon cleaner is non-abrasive and non-corrosive, but the supplied facts do not specifically confirm pressure-washer use.

Simple Green Industrial Cleaner and Degreaser combines a concentrated liquid formula with low-odor and biodegradable specifications, enabling buyers to dilute a gallon for cleaning jobs. Its non-abrasive designation suits users seeking an all-purpose degreaser rather than a product limited to engine surfaces.

The listed directions say to dilute with clean, ambient water, apply the solution, and leave it on the surface for one to two minutes. That gives users a clear preparation and dwell-time workflow before rinsing. Concentrated formula and one-gallon volume support making diluted solution for multiple jobs, while low odor and non-abrasive specifications may suit shared work areas and varied cleaning tasks. The supplied details do not specifically identify pressure-washer use, so check the product directions for that application.

Skip it if you need a cleaner explicitly listed for pressure washers; Oil Eater Original 1 Gallon names that use.

This fits buyers wanting a low-odor, concentrated all-purpose cleaner and a stated dilution-and-dwell routine. For engine cleaning through a pressure washer, its supplied product information leaves that specific application unconfirmed.

Listed on Amazon as: SMP13005 – Simple Green Industrial Cleaner and Degreaser

#5

5. 3D Grand Blast

• Volume: 1 gallons
• Material Features: Natural
• Form: Liquid

Best for: Large-batch engine-bay cleaning.

Why it ranks #5: Its concentrated gallon targets caked-on engine grease and is described as safe on metal, plastic, paint, and rubber; pressure-washer use is unverified.

Concentrated liquid in a one-gallon container gives 3D Grand Blast capacity for repeated engine-bay jobs, while its heavy-duty formula targets caked-on oil, grease, and grime. Its stated compatibility with metal, plastic, paint, and rubber also supports cleaning more than just engine components during a vehicle-care session.

The concentrated formula and one-gallon volume suit users who want a supply for multiple cleaning tasks rather than a single small application. Grand Blast is listed for engines, wheel wells, undercarriages, wheels, and exhausts, so one cleaner can cover several grime-prone areas. Its stated safety on metal, plastic, paint, and rubber broadens the surfaces it can address. The product information does not specify pressure-washer dilution or operating instructions, so follow the label when choosing an application method.

Skip it if you need published pressure-washer dilution directions; Oil Eater Original 1 Gallon specifically lists pressure-washer use.

Choose 3D Grand Blast for vehicle owners tackling engines alongside wheel wells, undercarriages, and exhausts with one concentrated gallon. Its listed surface compatibility is broad, but pressure-washer dilution guidance is not supplied here.

Listed on Amazon as: 3D Grand Blast Engine Degreaser – Heavy Duty Biodegradable Cleaner for Engines, Wheels, Exhausts & More – Fast-Acting, Non-Staining – Made in USA – 1 Gallon

#6

6. ATAS DIMER

• Volume: 900 ml
• Material Features: Acid-Free, Concentrated, Eco-Friendly…
• Form: Liquid

Best for: Concentrated engine maintenance.

Why it ranks #6: This concentrated, acid-free automotive engine cleaner removes oil and road grime, though its alkaline pH 13 requires careful material checks.

ATAS DIMER combines a concentrated, acid-free formula with automotive engine-cleaning applications, enabling buyers to target stubborn grease and oil in a compact 900-milliliter liquid. Its listed uses also include machinery, tools, and wheels, making it relevant when maintenance extends beyond the engine bay.

The concentrate is specified for engines, machinery, tools, and wheels, so one product can address several greasy surfaces during maintenance. Its acid-free formula is paired with a heavy-duty description for oil, dirt, and road grime, supporting routine cleaning without relying on an acid-based cleaner. At 900 milliliters, it is a smaller stated volume than gallon options, which matters for repeated or broad-area jobs. The safety information identifies a pH of 13 and cautions use on metal, rubber, and certain plastics.

Skip it if you need a gallon for repeated broad-area work; 3D Grand Blast Engine Degreaser is supplied in a one-gallon volume.

ATAS DIMER suits buyers seeking a concentrated engine and machinery cleaner for targeted maintenance. Its pH 13 warning makes surface suitability and careful handling important, particularly around metal, rubber, and certain plastics.

Listed on Amazon as: ATAS DIMER Heavy Duty Automotive Degreaser & Engine Cleaner Concentrate

#7

7. Chemical Guys Grime Reaper

• Volume: 473.2 ml
• Material Features: Fragrance Free
• Form: Liquid

Best for: Dilutable heavy-duty engine cleaner.

Why it ranks #7: The concentrated engine degreaser dilutes at one part product to six-to-nine parts water and rinses clean, but pressure-washer compatibility is not stated.

Chemical Guys Grime Reaper dilutes at one part product to six to nine parts water, enabling users to prepare solution for engine and vehicle grime. Its rapid-lift formula targets baked-on grease, oil, and road residue, while directions say it rinses clean without white residue stains.

The dilution range lets buyers prepare the cleaner for listed uses on engines, tires, wheel wells, and door jambs, stretching the 16-ounce liquid across multiple applications. Its rapid-lift action is described as breaking the bond between contamination and the surface, which helps heavy buildup release rather than smear and supports less scrubbing. The product is fragrance-free. Although its description mentions bulk gallon work, the supplied specifications identify this item as 16 ounces, a relevant limit for volume cleaning.

Skip it if you need a five-gallon pressure-washer supply; Oil Eater Original 5 Gallon explicitly lists pressure-washer use.

Grime Reaper suits buyers seeking a dilutable cleaner for engine and surrounding vehicle grime, with a stated rinse-clean finish. The listed 16-ounce volume makes it a smaller-supply fit for large, repeated jobs.

Listed on Amazon as: Chemical Guys Grime Reaper Engine Degreaser, Heavy Duty Cleaner, 16 oz

#8

8. Zep Cherry Bomb Auto+

• Volume: 128 fluid oz
• Material Features: Scented
• Form: Liquid

Best for: Multi-surface garage cleanup.

Why it ranks #8: This ready-to-use gallon tackles automotive oil and grease across listed surfaces including steel, chrome, rubber, and painted metal; washer use is unverified.

Zep Cherry Bomb Auto+ is listed for fiberglass, steel, chrome, stainless steel, painted metal, rubber, and finished concrete, enabling one cleaner to address varied vehicle and garage surfaces. Its formula targets heavy oil, grease, dirt, and grime on contact, making it relevant to demanding cleanup beyond engine bays.

The broad surface list lets a buyer consider the cleaner for vehicles and garage tasks without limiting use to one material: listed applications include RVs, boats, grills, appliances, garage doors, and shop tools. Its on-contact grease and oil breakdown supports fast cleanup, while the one-gallon liquid format provides a substantial supply for repeat work. The supplied information does not state pressure-washer directions, so buyers should consult the product label before using it in that equipment.

Skip it if you require stated pressure-washer directions; Oil Eater Original 5 Gallon specifically lists pressure-washer use.

Zep suits garage users who want a gallon for vehicle, marine, RV, and tool cleanup across several listed surfaces. The supplied details do not establish pressure-washer dilution or operating instructions.

Listed on Amazon as: Zep Cherry Bomb Auto+ Degreaser & Cleaner – For Auto, Marine, RV, & Home – 1 Gallon

#9

9. WD-40 Specialist Engine Degreaser

• Volume: 18 fluid oz
• Material Features: Recyclable
• Form: Spray

Best for: Foam for engine crevices.

Why it ranks #9: Its water-based foaming spray penetrates engine and machinery crevices, but the 18-ounce aerosol is not listed as pressure-washer compatible.

WD-40 Specialist uses a water-based foaming formula that penetrates crevices, enabling cleaner to cling to engine and machinery surfaces during application. Its nozzle sprays up to five feet, while an included straw provides a precision stream for reaching specific areas in automotive, industrial, or farm equipment cleanup.

The foam's stated crevice penetration helps address grime in harder-to-reach areas, while the low-residue, water-based formula is described as rinsing clean without residue. Buyers can use the nozzle's reach for broader application and switch to the straw's precision stream for targeted areas. Those features make the aerosol useful for equipment cleaning, but its spray format differs from a bulk concentrate intended for pressure-washer dilution. The listed volume is 18 fluid ounces.

Skip it if you need a bulk pressure-washer concentrate; Oil Eater Original 5 Gallon explicitly lists pressure-washer use.

This fits users targeting engine or machinery crevices with foam, reach, and a precision straw. Its 18-ounce aerosol format is better suited to direct application than preparing a large pressure-washer batch.

Listed on Amazon as: WD-40 Specialist Machine & Engine Degreaser Foaming Spray, 18 OZ

#10

10. Gunk Original Engine Degreaser

• Volume: 15 fluid oz
• Material Features: Unscented
• Form: Aerosol

Best for: Older greasy engine cleanup.

Why it ranks #10: This aerosol engine cleaner rinses with water after a 10-to-15-minute dwell, but it is not identified as suitable for pressure-washer use.

Gunk Original uses a deep-penetrating aerosol formula with a stated 10-to-15-minute dwell, enabling users to spray heavily soiled engines, wait, and rinse with water. Its focus on older, greasy, leaky engines makes it a targeted option for buildup rather than an all-purpose pressure-washer concentrate.

The spray-on, hose-off sequence reduces the need for scrubbing: saturate the engine, allow the listed dwell time for oil and grease to dissolve, then rinse. That workflow is aimed at baked-on contamination and hardworking engines, including older, greasy, leaky examples. The product is supplied as six 15-ounce aerosol cans, a format suited to individual spray applications. Because it is an aerosol spray rather than a listed pressure-washer concentrate, it serves a different application method.

Skip it if you need a pressure-washer-listed concentrate; Simple Green Pro HD explicitly names pressure washing as an application.

Gunk Original suits owners cleaning a heavily soiled engine with a spray, dwell, and hose-rinse routine. Choose another format if your priority is feeding diluted cleaner through pressure-washing equipment.

Listed on Amazon as: Gunk Engine Degreaser – Original Degreaser Cleaner Spray – Quickly Removes Tough Oil & Grease – Cleans Hardworking Engines – Rinses Easily with Water – 15 oz (Case of 6)