You may be forgiven for thinking that degreasers are an unessential item when it comes to your collection of car cleaning products. But poke your head under the bonnet of your car and chances are you’ll find a thin layer of grease, oil and muck coating just about everything. Not only does this make your car look like it’s been trapped in the boiler room of a ship, but it can also mask serious problems until it’s too late.
Small cracks and leaks, perished gaskets and even rust can be hidden under this gunk. So, keeping your engine bay clean is useful so you can spot these issues before they become serious money pits. Similarly, muddy tyres can also hide cracks, which is where tyre cleaners come rolling in.
The best degreasers at a glance:
Editor’s pick: Bilt Hamber Surfex HD – buy from Amazon.
Best eco-friendly degreaser: Autoglym Engine and Machine Cleaner- buy from Amazon.
Ideal for general use: Meguiar’s Heavy Duty Multi-Purpose Cleaner – buy from Amazon.
Car shampoo is often the ideal way to clean the outside of your vehicle. But a degreaser is the best way to clean an engine. It uses hydrophobic and hydrophilic molecules to help dislodge oil and allow you to simply wash the oil off. We’ve chosen our favourite examples, looking at price, environmental impact and effectiveness so you know which one is perfect for you and your engine.
The best degreasers
Editor's pick
Available as either a one-litre spray or a five-litre bottle, it can be diluted to clean paintwork, carpets, wheels and tyres. It's also great value for money and top quality too.
Pros
- Doubles as APC
- Effective while environmentally friendly
Cons
- 500ml isn't the greatest capacity available
The best eco friendly degreaser
Pros
- Effective in removing engine filth
- Water-based solvent makes it environmentally friendly
Cons
- Quite a small bottle
The best degreaser for really mucky surfaces
Pros
- The most effective on the toughest grease stains
Cons
- Handle with care on rubber and paintwork areas
The best bulk degreaser
Pros
- Useful when dismantling and restoring an engine
- Comes in huge 5L capacity
Cons
- Can leave a white film after use
The best degreaser for general use
What's impressive about this is that it can be sprayed onto metal, rubber, plastics and fabrics and clean without needing to be diluted like the Bilt Hamber option. Still, it's not a particularly good degreaser that needs to be remembered when shopping.
Pros
- A comprehensive spray cleaning bottle for a number of jobs
Cons
- Wasn't strictly designed as a degreaser
Best single brush for cleaning engine grease
Pros
- Great value
- Good quality brush
Cons
- It won't be able to reach the deepest areas of your engine bay
What you need to know about degreaser
Is degreaser dangerous?
Yes, degreasers aren’t something you particularly want to ingest. Most of them will cause eye and skin irritation. The solvent-based ones are flammable and can cause drowsiness or dizziness.
Old kerosene-based degreasers are particularly nasty to pretty much anything living. As water-based options are far better at removing grease, there’s no real need to rely on these solvent-based options anymore.
Water-based options are often biodegradable which means you won’t be damaging the planet while you clean your engine bay. Talk about eco-friendly car care.
Why should I keep my engine bay clean?
A clean engine bay may seem unnecessary, considering you hopefully don’t spend a lot of time under your bonnet. But it makes a lot of sense to keep it clean. Not only will a clean engine bay help when selling, but it will make catching any mechanical issues easier to spot before they become serious.
How to clean your car engine bay
• Run your engine for a couple of minutes (five should do) and then turn your engine off. This will heat the deposits and make removing them easier.
• Lift the bonnet and make sure the engine bay is cool enough that you won’t roast your fingers as you clean the engine.
• Remove the engine cover if there is one and put it to the side. You can clean that separately with an all purpose cleaner (APC) and dressing.
• Prepare the engine bay for cleaning by covering the sensitive electric bits in plastic bags. Make sure to cover the battery (disconnect the negative terminal too), ignition wires and ECU. Also, cover the air filter to keep everything safe.
• Apply the degreaser to the engine bay, being liberal with how much you add. You can add some to your engine cover too.
• Allow a couple of minutes for the degreaser to penetrate the grease. Then scrub it with an appropriate brush to make sure you’ve loosened the grease.
• Wash it down with a hose and remove any existing water with an old drying towel.
• When the engine is dried, remove the plastic bags and reattach the engine cover.
How we choose
All of these degreasers for car care have been hand-selected by our team of experts who have spent hours investigating and researching degreasers for car care to make it easier for you to find the very best, and we’d never recommend a product we don’t believe in.
Where possible, we also test and share the latest and best products you should know about.
Ryan Gilmore is the Deputy Autos and Tools Editor for Parkers, specialising in car cleaning and hand tools. A veteran car cleaner; if it details, waxes or washes he’ll be on hand to make sure it’s worth your money.
Sign up to the Parkers Newsletter to keep up to date with more of the latest reviews, news, and recommendations from the Parkers team.
Just so you know, whilst we may receive a commission or other compensation from the links on this page, we never allow this to influence product selections – read why you should trust us.
Just so you know, we may receive a commission or other compensation from the links on this website - read why you should trust us.
