The real difference between "cheap" petrol and branded petrol: what happens to your injectors in the long run, according to mechanics

Do you think saving €0.15/l at the petrol station is worth it if your injectors can fail before 100,000 km? Choosing “cheap” petrol may seem like an immediate saving, but in the long run your injectors (and your wallet) could end up paying a high price.

Types of petrol and their composition

There are two key differences between “cheap” petrol and branded petrol: the level of detergent additives and the quality of blend control. Most European fuels are E5/E10 (up to 10% ethanol), and the octane rating (95/98) affects combustion, not cleaning. What makes the difference is the presence of PEA additives (the most effective for removing deposits) and the dosage of anti-corrosion agents.

Effects on the engine and injectors

Injectors depend on a precise spray pattern. Fuels with fewer detergents encourage deposit formation on the nozzle and injector body, which alters the spray pattern and reduces flow rate.

Practical consequences: loss of power, higher consumption, misfires and increased emissions. In direct-injection engines the problems appear more clearly due to high pressures and sensitivity to the spray pattern.

What you need to know

• Immediate saving: €0.10–0.25/l usual difference between cheap and branded petrol.
• Technical risk: deposits that reduce injector flow by 5–15% depending on the degree of fouling.
• Maintenance cost: professional cleaning ~ €60–120; replacing one injector ~ €300–800 (depending on the car and labour).
• Best prevention: PEA additives and occasionally refuelling at high-turnover stations.

Opinions from expert mechanics

“In the workshop we see two profiles: cars that use branded petrol and reach 200,000 km without touching the injectors, and vehicles that constantly refuel with cheap fuel and need cleaning or replacement before 120,000 km,” explains Juan Pérez, workshop manager with 15 years of experience. Another mechanic adds: “Ultrasonic cleaning and PEA additives fix many cases, but when the nozzle is already damaged, the only remedy is replacing the injector.”

Tips for good maintenance

• Refuel at high-turnover stations and well-known brands from time to time; you don’t need to do it always, but do it regularly.
• Use injector cleaners based on PEA every 30,000–40,000 km or if you notice jerking, uneven idling or higher consumption.
• Change the fuel filter according to the maintenance schedule; a clogged filter accelerates injector problems.
• Avoid keeping the tank always near empty: more water and sediment accumulate, increasing the risk of corrosion.
• If you have direct injection, be stricter: these engines are more sensitive to deposits on valves and injectors.

Cost-benefit ratio (practical scenario)

If you drive 12,000 km/year and consume 50 l/month, a difference of €0.15/l means a saving of €90/year. However, one professional cleaning or an occasional injector replacement can cost between 60 and 800 euros. Over 5 years you might save about €450 in fuel, but a single injector replacement or frequent cleaning can wipe out that benefit or leave you with a net loss.

Final conclusion

The saving per litre is tempting, but the trend in the car park (more direct-injection and turbocharged engines) increases sensitivity to deposits. My practical recommendation: if you want to save, alternate cheap refuelling with refuelling at well-known brands, apply PEA cleaners according to mileage, and don’t ignore symptoms (jerking, smoke, consumption). In the short term you’ll save a few cents; in the medium term, preventing problems with cheap maintenance avoids expensive repairs.