What are the top-rated car engine cleaners for the best value under £50?

Water-based, deep-penetrating 500ml trigger spray designed to remove grease, oil and road grime from engines and machinery. Fast-acting formula intended for vehicle engines, industrial and garden equipment; apply, let soak, agitate if needed, then rinse. Suits users who need an easy-to-use spray degreaser for routine engine cleaning.

Redex Petrol System Cleaner is a 500ml fuel additive that cleans fuel injectors and the petrol system, restores performance, reduces emissions and protects against corrosion from E10 fuel. It contains a concentrated dosing system (2.5ml per litre) and is supplied with dose markings for easy use, suitable for regular maintenance.

Water-based engine and machine cleaner that rapidly dissolves oil, grease and grime. Safe for metal, plastic and rubber components and designed to be sprayed on, agitated with a brush and rinsed off; supplied in 1 litre bottles and sold by Autoglym and major retailers.

Cataclean Petrol 500ml is a one-shot fuel and exhaust system cleaner that works pre- and post-combustion to remove carbon, gum and resin from fuel system components and the exhaust, including the catalytic converter and oxygen sensors. It is a patented solvent blend intended to reduce emissions and improve fuel economy and performance, for use every ~3,000 miles or three months.

Redex Petrol System Cleaner 250ml is a fuel-additive designed to clean injectors and the fuel system, restore performance, and protect against corrosion from E10 fuel. It treats two tankfuls per bottle and is suitable for regular use in petrol engines.

Solvent-based tar and glue remover in a non-drip gel/aerosol spray that softens and dissolves tar, glue and sap for easy wipe-off. Designed for exterior use on paint, glass and wheels and intended to be used spot‑wise then rinsed and re‑waxed. Best for quick removal of stubborn road tar and adhesive residues.

325ml one-shot petrol injector cleaner that cleans and lubricates injectors, prevents deposits for up to 5,000 km, and is safe for catalytic converters and oxygen sensors. Treats roughly 30-70 litres of fuel and is presented as compatible with capless fuel systems and E10 fuel. Suitable for routine maintenance to improve idling, cold starts, power and fuel economy.