Cleaning a greasy engine requires more than just soap and water. We researched and compared the top degreasers on the market using manufacturer specifications, published industry standards (like OSHA and VOC regulations), and aggregated owner feedback from thousands of real users. Our evaluation focuses on performance, safety, and value to help you choose the right product for your engine bay.
| Photo | Product | Score | Buy |
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Chemical Guys Signature Series Orange Degreaser Top Pick Biodegradable, pH neutral, concentrated formula |
9.0 | 🛒 Check Price |
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Meguiar's D10801 Super Degreaser Best Value Concentrated, pH neutral, safe on clear coat |
8.7 | 🛒 Check Price |
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Gunk EB1 Engine Degreaser Best Solvent-Based Aerosol spray, petroleum solvent formula |
8.4 | 🛒 Check Price |
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Simple Green 19128 Industrial Cleaner & Degreaser Eco-Friendly Biodegradable, non-toxic, concentrated |
8.1 | 🛒 Check Price |
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CRC 05089 Brakleen Brake Parts Cleaner Fast Evaporating Aerosol, non-flammable, chlorinated solvent |
7.8 | 🛒 Check Price |
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WD-40 Specialist Heavy-Duty Degreaser All-Purpose Trigger spray, water-based formula |
7.5 | 🛒 Check Price |
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Purple Power 43464 Industrial Degreaser Heavy Duty Concentrated, alkaline formula |
7.3 | 🛒 Check Price |
1. Chemical Guys Signature Series Orange Degreaser: Top Pick
Chemical Guys Signature Series Orange Degreaser is a biodegradable, pH neutral concentrate that we found highly effective on engine grease based on owner feedback and spec sheets. It dilutes up to 1:4 for tough jobs and leaves a pleasant orange scent. In our evaluation, it consistently removed baked-on oil and grime without damaging aluminum or painted components, and it rinses cleanly with water.
However, some users reported that it requires more scrubbing on extremely thick carbon deposits compared to solvent-based degreasers. If you need a one-step spray-and-hose solution for heavily caked grease, you might prefer a stronger solvent formula. This is best for regular engine cleaning and those who prioritize eco-friendly products.
- Concentrated formula dilutes up to 1:4 for heavy grease
- Biodegradable and pH neutral safe on most surfaces
- Pleasant orange scent, no harsh chemical fumes
Pros: Effective on heavy grease without etching; Versatile dilution ratios for light to heavy cleaning; Safe on aluminum and painted surfaces
Cons: Requires thorough rinsing to avoid residue
2. Meguiar's D10801 Super Degreaser: Best Value
Meguiar’s D10801 Super Degreaser is a pH neutral concentrate that offers great value for money. Based on manufacturer specs and owner reviews, it dilutes effectively and cleans moderate engine grease without damaging surfaces. We compared its performance to others and found it ideal for routine engine bay cleaning, especially for those who want a safe, low-VOC option.
On the downside, it struggles with heavy, baked-on grease and may require multiple applications or stronger dilution. If you frequently tackle extremely dirty engines, a more aggressive solvent may be better. This is a solid choice for maintenance cleaning and for users who need a versatile, safe degreaser.
- Concentrated formula dilutes up to 1:10 for light cleaning
- pH neutral safe on clear coats and aluminum
- Low VOC formula compliant with regulations
Pros: Excellent value per gallon when diluted; Safe on sensitive surfaces like clear coat and plastic; Effective on moderate grease and road grime
Cons: Less effective on heavy carbon buildup without agitation
3. Gunk EB1 Engine Degreaser: Best Solvent-Based
Gunk EB1 Engine Degreaser is a classic solvent-based aerosol that we found highly effective on stubborn grease based on owner feedback and product specs. It sprays on easily and penetrates quickly, making it a favorite for heavy-duty cleaning. In our evaluation, it removed years of built-up grime with minimal scrubbing, and the corrosion inhibitors help protect metal surfaces.
However, its strong solvent smell and high VOC content make it less suitable for enclosed spaces or environmentally conscious users. It can also damage certain plastics if left on too long. If you need a quick, powerful degreaser for occasional heavy cleaning and are prepared for the fumes, this is a top choice.
- Fast-acting solvent cuts through heavy grease
- Aerosol spray for easy application on engine bays
- Contains corrosion inhibitors for metal protection
Pros: Very effective on thick, baked-on grease; Easy to use with no mixing required; Leaves a protective film to prevent rust
Cons: Strong chemical odor and high VOCs
4. Simple Green 19128 Industrial Cleaner & Degreaser: Eco-Friendly
Simple Green 19128 Industrial Cleaner & Degreaser is a well-known biodegradable concentrate that we evaluated for engine cleaning. According to manufacturer specs and user reviews, it is safe on most surfaces and effective on light to moderate grease. We found it particularly good for those who want a non-toxic, low-odor option for regular engine bay maintenance.
However, it struggles with heavy, baked-on grease and often requires agitation or multiple applications. If you need a heavy-duty degreaser for a severely greasy engine, this may not be strong enough. It is best for eco-conscious users and routine cleaning.
- Biodegradable and non-toxic formula
- Concentrated dilutes up to 1:30 for light cleaning
- Safe on most surfaces including aluminum and plastic
Pros: Environmentally friendly with no harsh fumes; Versatile for many cleaning tasks beyond engines; Safe on sensitive materials when diluted properly
Cons: Requires more scrubbing on heavy grease
5. CRC 05089 Brakleen Brake Parts Cleaner: Fast Evaporating
CRC 05089 Brakleen is primarily a brake parts cleaner but we included it because many owners use it for spot-cleaning engine grease. Based on spec sheets and feedback, it evaporates quickly without leaving residue, making it ideal for sensors and electrical components. In our evaluation, it works well for small areas but is impractical for full engine degreasing due to cost and aerosol volume.
However, its chlorinated formula has health and environmental concerns, and it is not intended for large surfaces. If you need to degrease an entire engine, this is not the right product. It is best for targeted cleaning of small, sensitive parts.
- Non-flammable and fast-evaporating formula
- Leaves no residue for sensitive components
- Ideal for cleaning brake parts and small engine areas
Pros: Evaporates quickly without water rinsing; Effective on oil and grease in tight spots; Non-flammable for safe use near sparks
Cons: Not designed for large engine bay cleaning
6. WD-40 Specialist Heavy-Duty Degreaser: All-Purpose
WD-40 Specialist Heavy-Duty Degreaser is a water-based, ready-to-use spray that we evaluated for light engine cleaning. According to owner feedback and specs, it is easy to use and safe on most surfaces, making it a good all-purpose option. In our comparison, it handles moderate grease but requires more product and effort on tough grime.
However, it is not effective on heavy, baked-on grease and may not be cost-effective for large engines. If you need a quick, low-fuss cleaner for a mildly dirty engine, this works. For deep cleaning, you will need a stronger concentrate.
- Water-based with no harsh solvents
- Ready-to-use trigger spray for convenience
- Safe on most surfaces including painted metal
Pros: Convenient spray bottle, no mixing needed; Mild odor and safer for indoor use; Works well on light to moderate grease
Cons: Not strong enough for heavy carbon deposits
7. Purple Power 43464 Industrial Degreaser: Heavy Duty
Purple Power 43464 Industrial Degreaser is a strong alkaline concentrate that we found effective on heavy grease based on manufacturer specs and user reviews. It cuts through thick oil and carbon deposits quickly, making it a favorite for heavy-duty cleaning. In our evaluation, it performed well on iron and steel but required careful handling.
However, its alkaline nature can etch aluminum and strip paint if not rinsed promptly. It also has a strong odor and requires protective gear. If you have sensitive engine components or painted surfaces, this is not ideal. It is best for industrial-style cleaning of non-sensitive parts.
- Strong alkaline formula for heavy grease
- Concentrated dilutes up to 1:5 for tough jobs
- Effective on oil, grease, and carbon
Pros: Powerful on heavy grease and oil; Good value when diluted; Works well on engine blocks and parts
Cons: Can damage aluminum and painted surfaces if left too long
Frequently Asked Questions
Can I use a degreaser on a hot engine?
It is generally not recommended to use a degreaser on a hot engine. Most degreasers are designed for cool or warm surfaces, and applying them to a hot engine can cause rapid evaporation, reduced effectiveness, and potential damage to rubber or plastic parts. Always let the engine cool to a safe temperature before cleaning.
Do I need to cover electrical components before spraying degreaser?
Yes, it is wise to protect sensitive electrical components like the alternator, distributor, and battery terminals. Use plastic bags or waterproof covers to prevent moisture and degreaser from entering electrical connections. While many degreasers are safe on plastics, water or residue can cause short circuits.
How long should I let a degreaser sit on the engine?
Follow the manufacturer’s instructions, but generally 3 to 10 minutes is sufficient for most degreasers. Allowing it to sit too long can cause damage to painted surfaces or rubber seals. For heavy grease, you may need to agitate with a brush. Do not let it dry completely.
Is it safe to use a degreaser on aluminum engine parts?
Many degreasers are safe on aluminum, but alkaline or solvent-based formulas can cause etching or discoloration. Look for pH neutral or aluminum-safe labels. Always test on a small inconspicuous area first and rinse thoroughly.
Can I use a pressure washer with a degreaser?
Yes, a pressure washer can help rinse away degreaser and grease effectively. However, use a wide spray pattern and avoid high pressure directly on seals, gaskets, and electrical components. A foam cannon can also help apply the degreaser evenly.
Our Verdict
After researching and comparing manufacturer specs, safety standards, and owner feedback, our top pick is the Chemical Guys Signature Series Orange Degreaser for its balanced performance, safety, and eco-friendly formula. For budget-conscious buyers, the Meguiar’s D10801 Super Degreaser offers excellent value and safe cleaning. Choose based on your specific needs: heavy grease requires solvent-based options like Gunk EB1, while routine maintenance is well served by Simple Green.
Last reviewed and spec-checked: May 24, 2026. We re-check our picks and listings periodically.
