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Discover What Has Caused Concern Among Owners of Chevrolet Onix and Tracker, An Unexpected Problem in the System That Can Compromise Safety and Maintenance, Requiring Special Attention to Avoid Losses and Risks While Driving.
Since Chevrolet introduced oil-bathed timing belt engines in models such as Onix, Onix Plus, Tracker, and Montana, numerous owners have begun reporting problems related to this system.
The most concerning among the reports is the sudden difficulty in engaging the brake, with the pedal becoming extremely hard, compromising braking and generating insecurity while driving.
This type of engine, which uses a belt directly bathed in the engine’s lubricating oil, offers benefits such as less noise and better energy efficiency.
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On the other hand, it requires rigorous maintenance and the proper use of the oil specified by the manufacturer to avoid serious mechanical failures.
The Vacuum Pump Failure and Its Impact on Braking
According to experts consulted by the report, the problem is directly related to a failure in the vacuum pump, an essential component for brake assistance.
This pump is integrated into the engine’s lubrication system, sharing the same oil circuit that keeps the timing belt lubricated.
When maintenance does not follow the recommended specifications, especially regarding the type and quality of the lubricating oil, debris from the degraded belt can clog the pipes of the vacuum pump.
As a result, the pump overheats, fails, and causes the loss of brake assistance, leaving the pedal hard and braking compromised.
Features of CSS Prime Engines
The CSS Prime engines — which equip the domestic Chevrolet 1.0 aspirated, 1.0 turbo, and 1.2 turbo three-cylinder models — are the ones that feature this oil-bathed belt characteristic.
Experts explain that, unlike traditional timing belts, which operate dry, the belt directly lubricated by oil depends on the quality of the lubricant to maintain its durability.
Professor Clayton Zabeu from the Mauá Institute of Technology highlights that “the specification of the oil and the change interval are crucial for the longevity of the belt.”
Nelson Morales, coordinator at Dayco, the manufacturer of timing belts, adds that “any degradation or contamination of the oil can accelerate belt wear, compromising the entire engine synchronization system.”
In practice, using oil outside GM’s standards can cause the belt to degrade prematurely, releasing fragments that circulate through the system and clog the vacuum pump.
This scenario causes the sudden hardening of the brake pedal, putting the safety of vehicle occupants at risk.
Real Reports from Owners
Real cases demonstrate the impact of this failure.
Rodrigo P. (fictitious name), a doctor and owner of a 2023 Chevrolet Onix Plus, experienced a moment of tension when he witnessed the brake pedal harden while his wife was driving in the city.
He recounts that his wife had to use the handbrake to control the car and managed to return home without accidents.
Rodrigo bought the vehicle in 2024, with 65,000 km, from a multi-brand store, and since he had done the inspections outside the authorized network, he had no valid warranty.
Only after a diagnosis at a private workshop did he discover that the vacuum pump was clogged with debris from the belt and had to replace the component, spending around R$ 1,120.
Even after the repair, the problem occurred again, which led him to part with the car.
Official Stance of Chevrolet
In an official statement, Chevrolet claims that there is no failure in the braking system of the affected models and that safety remains guaranteed.
The automaker emphasizes the importance of rigorous maintenance with lubricating oils according to the indicated specifications to avoid mechanical damage.
In November 2024, General Motors extended the warranty of the timing belt in CSS Prime engines to 240,000 km, and since April 2025 offers a special action to renew this warranty on Onix and Onix Plus models from 2019/2020, purchased used with irregular maintenance history.
This service, available until December 2025, includes system inspection, oil and filter change for R$ 660, an amount compatible with regular periodic inspections.
If wear or contamination is detected, the belt can be replaced for R$ 700, a price that includes parts and labor, ensuring significant savings for consumers.
Limitations of the Special Action and Complaints
However, GM’s special action only covers the Onix and Onix Plus models, leaving out the Tracker and Montana, although equipped with the same engines.
According to Chevrolet, these other models do not show a significant number of similar complaints.
André Kaschel, owner of a Tracker, expresses indignation at having to bear the repair costs out of warranty and the risk that the defect posed to his family.
He reports that the problem generated fear and insecurity, despite having kept the car well maintained and with low mileage.
Manufacturer Recommendations and Maintenance Care
GM also emphasizes the need to strictly follow the recommended inspection interval in the owner’s manual, which indicates an oil and filter change every 10,000 km or 12 months, whichever comes first.
For vehicles mainly used in cities, heavy traffic, or severe roads, it is recommended to reduce this interval to 5,000 km or six months.
However, Chevrolet does not detail a specific timeframe for severe use, unlike other manufacturers, such as Ford, which establishes an inspection every 5,000 km or three months under those conditions.
Another important point is that maintenance should preferably be carried out at authorized Chevrolet dealerships to maintain the warranty valid.
This issue reinforces the need for owner awareness to avoid using inappropriate oils or procedures outside the specifications, which jeopardize vehicle performance and the safety of passengers.
Increased Attention for Those with Oil-Bathed Belt Engines
With the popularization of the oil-bathed belt in compact engines, care with preventive maintenance becomes even more essential to avoid serious failures like the one affecting the braking system.
Are you, who owns a Chevrolet with a CSS Prime engine, attentive to your car’s maintenance recommendations? Have you faced any issues related to the oil-bathed belt? Share your experience!
Tenho um onix 2023 turbo 1.0 , todas as revisões na concessionária!!! Carro muito ruim de freio é horrível parece que esta frenando em uma lata pura Tenho medo e muito cuidado quando estou dirigindo, também me venderam um coisa e me entregaram outra o Wi-Fi nativo que prometeram não tem apesar de eu pagar o plano no valor de 99,99 reias mensalmente… tenho vontade de procurar um advogado especialista nesta área para tentar resolver, Também o carro teve que voltar para a concessionária três vezes por a bateria não carregava me deixou na mão várias vezes… não recomendo fiz uma ocorrência no Procon da minha cidade mais nada consegui…
Sera que a Chevrolet agora toma **** e tira está bomba? Ou só vai fazer quando o MP obrigar a exemplo de uma borracha de centavos com a VW para parar de decepar dedos no rebatedor do banco do Fox?
Aconteceu comigo, carro alugado da Movida, era carro da empresa onde trabalhava, manutenção das locadoras é feito em fundo de quintal, eu acompanhei e colocavam qualquer óleo. Numa viagem fiquei sem freio no carro, sorte que era madrugada, senão tinha me matado. Acendeu a luz de injeção, cortou a turbina e quando fui parar no acostamento não tinha freio. Fiquem alertas, se acender a luz de injeção vc já não tem mais freio no carro!