Mercedes-Benz C300 gas smell due to secondary fuel pump replacement and sunroof repair needed on Mercedes-Benz C300

Submitted by Vehicle Owner · Sep 7, 2025
Published by RepairPal

Problem overview

Some Mercedes-Benz C300 owners report experiencing a gas smell, which may indicate underlying issues such as fuel leaks that pose significant fire hazards due to toxic gasoline fumes. This odor can arise from leaking fuel components, such as a fuel tank vapor line or a fuel pump seal, particularly after filling up the tank. Additionally, some owners of the W205 models with the M274 engine have noted that the high-pressure fuel pump is a common source of these fuel smells, and a class action lawsuit has been filed regarding fuel leak defects in 2015-2019 C-Class vehicles, potentially necessitating a fuel pump replacement. Furthermore, while addressing the gas smell is critical, some owners also highlight the importance of sunroof repairs to prevent leaks and interior odors. It is recommended that owners have a qualified technician inspect their vehicle to diagnose the gas smell's specific causes and evaluate the need for repairs, ensuring safety and optimal vehicle performance.

2 people reported this problem
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Mercedes-Benz C300 vehicles with this problem

1 model year affected
Average mileage: 51,000 miles
(51,000 - 51,000)

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