AutosMechanics warn: Premium fuels may damage older engines, suggest budget-friendly alternatives

Mechanics warn: Premium fuels may damage older engines, suggest budget-friendly alternatives

Fuel filler.
Fuel filler.
Images source: © Adobe Stock | Pawel Kacperek

12:17 PM EST, February 21, 2024

Fuel companies brand their premium fuels as always beneficial and harmless, a claim mechanics don't fully believe. Independent tests executed by ADAC demonstrate that consumption of premium fuel can decrease by 1-5 percent, but these fuels typically cost more than 5 percent higher. While they can theoretically boost a car's performance, few drivers actually make full use of the engine's potential.

Even these possible benefits might be insignificant if such fuel is used in an older engine with high mileage. Adam Lehnort, expert of the ProfiAuto Service network, collected data and observations from mechanics on this topic.

Lehnort explains how premium fuels, which should theoretically be beneficial, could actually damage cars with high mileage. The refining and cleaning additives in these fuels might wash out accumulated pollutants in the engine, which then mix with the oil in the oil pan. This might initially seem advantageous, as the engine becomes clean and the oil is regularly changed.

However, carbon deposits washed away in this process can undermine the seal of the piston in the cylinder, decreasing the compression ratio and reducing engine power, rather than increasing it. Furthermore, detergents in premium fuels may wash out impurities in the fuel system, potentially harming the injectors.

Lehnort strongly warns against using premium fuels and those with a higher octane number in engines that lack a knock sensor. This warning primarily applies to engines from the 90s or older, which are still quite common, and their owners do not always cut corners.

The expert in the ProfiAuto Service network notes that premium fuels contain anti-knock additives meant to prevent the pistons, valves, and even the engine head from burning as a result of detonation. If the engine doesn't have a knock sensor, fuel with a higher octane number can slow the combustion process to the point where the engine loses its original power.

Lehnort states that to reap the benefits of fuel with a higher octane number, one would need to adjust the ignition advance angle and consistently use such fuel.

Mechanics propose fuel chemical additives as an alternative to premium fuels, which can be used every 3100 miles, for instance. These additives, designed specifically for engines, are a potential replacement for premium fuels, according to mechanics.

This particularly pertains to molecular engineering products with nano and microtechnology (which includes graphene). Their effects, confirmed under road conditions, long-distance tests, on test stands, and in professional sports, have been noted. Comparatively, this is a more budget-friendly alternative when compared to the regular use of enhanced fuels.

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