Assessment for increasing ethanol content in gasoline did not include durability test

The numbers appear in the 2026 edition of the Circulating Fleet Report, published by Sindipeças (National Union of the Automotive Component Industry), with data referring to 2025.

The document shows a significant drop in the circulation of gasoline-powered cars over the last ten years. In 2016, there were 11.9 million. Still, these vehicles remain common, both among older models and in dealerships.

The protocol for the adoption of the E30 was defined in December 2024. Over the following year, it was up to IMT (Instituto Mauá de Tecnologia), Folha's partner in vehicle tests, to evaluate popular cars from the 1990s, a time when the anhydrous ethanol content in gasoline was 22%, and imported models with around ten years of use fueled with the new mixture.

The results showed that, in the short term, the problems would be limited to a small increase in fuel consumption. As a safety margin, the evaluations also used the E32, now approved. However, durability tests were not carried out, which would require more time.

Renato Romio, professor and head of the IMT's Engine and Vehicle Laboratory, explains that the criteria were defined by a committee made up of representatives from different entities, including the government and car manufacturers, and applied by the institute.

“The parts of the tests relating to the drivability of the vehicles, with assessment of cold starting, were carried out with 32% anhydrous ethanol added to gasoline, due to the tolerance margin of two percentage points”, says Romio. “Emissions measurements were made with E30, but durability assessments were not carried out.”

The professor explains that it is up to the CNPE (National Energy Policy Council) to decide whether the requested information is sufficient and, from there, approve or reject changes in the ethanol content of gasoline.

In practice, problems have been occurring for some time, especially in imported vehicles equipped with more sophisticated electronic injection systems. These models are more sensitive to low-quality fuels or those with a high ethanol content. Many were approved and produced before recent changes in legislation.

"Right now, we are repairing an Audi Q7 that had a problem with the fuel. The car was refueled on the road during a trip and there was no premium gasoline available at the stations, making it necessary to use regular gasoline", says Bruno Tinoco, owner of the Motorfast workshop.

“We removed the fuel at the workshop, refueled with Podium, a premium line from Petrobras stations, and carried out some procedures to normalize operation and turn off the injection system failure light.”

The premium gasoline mentioned by Tinoco is not restricted to Podium. Ipiranga Ipimax Pro and Shell V-Power have similar characteristics, such as higher octane and, mainly, ethanol content limited to 25%. The price, however, is high. At gas stations in São Paulo, a liter costs around R$10.

"These imported cars have already arrived in Brazil suffering from gasoline with a high ethanol content. A car developed, for example, for European fuel and fueled with regular Brazilian gasoline may present problems such as carbonization, which causes failures in the cylinder seals", says the owner of Motorfast.

Tinoco cites the case of a Mercedes-Benz GLC 2.0 turbo, year 2019, serviced by the workshop. Carbonization, the formation of a dark crust on parts of the engine and injection system caused by the irregular burning of fuel, caused damage to the spark plugs, injection nozzles and gasoline pressure sensor. The repair budget came to R$11,169.

Faced with cases like this, entities linked to the automotive sector sent a letter to the federal government stating that there are no conclusive studies that prove the safety of increasing the mixture of ethanol in gasoline from 30% to 32%.

Older models in circulation in Brazil were developed to run on gasoline containing 22%, 25% or 27% anhydrous ethanol.

"There is a very strong possibility that we will have vehicles parked on the street, with a broken engine. This is the extent of the discussion and, therefore, we need more time to address the issue", says Marcelo Godoy, president of Abeifa, an association that brings together vehicle importers.

"We understand the benefits of the measure, but we need predictability to align this change with the matrices. There is an engineering issue to be resolved, and this requires time and discussion. We were against such an abrupt change", he adds.

Despite complaints, decisions about the ethanol content in gasoline have historically had the economic factor as the main element. This was what happened in 1989, when the scarcity of biofuel led to a reduction in the proportion.

In March of that year, the percentage of alcohol in the mixture dropped from 22% to 17%. Fuel was scarce at stations, which led to queues for fueling and devalued ethanol-powered cars, which were the majority among zero-kilometer models at the time.

I welcome with optimism the increase in the percentage of ethanol in gasoline to 32%, says Hugo Motta

President of the Chamber highlighted that the measure brings stability and security to national production