Mercedes-Benz S65 AMG Smells Like Gas

Diagnosing Fuel Odor Issues in Your Mercedes-Benz S65 AMG and Essential Safety Measures to Take

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
15% chance it's the
Gas Cap
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40% chance it's the
Emissions Control System
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45% chance it's
Something else
The most common reasons a Mercedes-Benz S65 AMG smells like gas are the gas cap, the fuel system, or the emissions control system.
  • Gas Cap: A loose or damaged gas cap can cause fuel vapors to escape, triggering the check engine light and potentially affecting fuel system pressure.
  • Emissions Control System: A faulty emissions control system can lead to increased hydrocarbon emissions and trigger the check engine light due to malfunctioning components like the EGR valve or O2 sensors.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a Mercedes-Benz S65 AMG smells like gas?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A failing catalytic converter can cause a vehicle to fail emissions tests and turn on the check engine light. The exhaust might have an unusual smell. A restricted catalytic converter can result in a loss of engine power.

» LEARN MORE: How to tell if your catalytic converter is failing

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. The canister may also cause difficulty starting the engine, a rough idle, and poor fuel mileage.

When the fuel filter begins to clog, the engine suffers from fuel starvation. This will cause a significant reduction in power and may also cause a misfire. These conditions may be intermittent, or constant and worsen over time. As the issue progresses, the engine may being to stall immediately after starting, fail to start, hesitate under throttle, or stall at particular angles on hills.

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. A fuel tank leak may also cause difficulty starting the engine, a rough idle, and poor fuel mileage. When a fuel tank is simply corroded to the point of failure, the exterior tank condition rarely shows damage. The inside of the fuel tank will be rusted or corroded, and rust flakes or other debris may be floating in the fuel.

For most vehicles, the only symptom will be a check engine light or fuel tank filler cap light illuminating on the driver instrument cluster. This is to signal that there is an evaporative emissions (EVAP) leak. In some situations, the vehicle may take longer than normal to start, or, more rarely, the engine may not start at all. on-board diagnostic (OBD) trouble codes will refer to EVAP system failures such as a small or massive EVAP system leak. Lastly, the powertrain control module may notice a lean running condition, which could even lead to random and infrequent misfires.

Troubleshooting Gas Smell in a Mercedes-Benz S65 AMG

When faced with a gas smell in your Mercedes-Benz S65 AMG, it's essential to adopt a methodical diagnostic approach to pinpoint the source of the problem. Start by visually inspecting the area beneath your vehicle for any signs of fuel leakage, particularly around the gas pump and fuel lines. Puddles or wet spots can indicate a high-pressure rubber hose failure, which is a relatively straightforward fix. Next, examine the rubber fuel line in the engine compartment, ensuring that all clamps are secure, as loose connections can lead to leaks, especially in colder temperatures. If you notice any deterioration or cracks in the hoses connected to the pump or filter assembly, these may also be contributing to the gas smell and should be replaced. If these initial checks do not resolve the issue, consider the possibility of more complex problems, such as a gas tank defect, particularly in models from 2003 to 2009, which may require professional intervention. By following this step-by-step approach, you can effectively troubleshoot and address the gas smell, ensuring both your safety and the longevity of your vehicle.

What Could Cause a Gas Smell in a Mercedes-Benz S65 AMG?

When you detect a gas smell in your Mercedes-Benz S65 AMG, it’s essential to consider several common problems that could be the source. One of the first areas to check is the gas cap; a faulty or improperly sealed gas cap can allow fuel vapors to escape, leading to noticeable odors inside the vehicle. Additionally, inspect the fuel system for any leaks or damaged hoses, as these can also contribute to gas smells. Another potential culprit is the emissions control system, which, if malfunctioning, may not adequately manage fuel vapors, resulting in unpleasant odors. Lastly, consider the possibility of vapor escapes due to exhaust issues, which can further exacerbate the problem. Addressing these issues promptly is crucial not only for your safety but also to maintain the performance of your vehicle and avoid costly repairs down the line. By systematically diagnosing these common problems, you can ensure a safer and more enjoyable driving experience in your Mercedes-Benz S65 AMG.

What to Do If Your Mercedes-Benz S65 AMG Smells Like Gas?

If you notice a gas smell in your Mercedes-Benz S65 AMG, it’s essential to act quickly, as this could indicate serious issues that may compromise your safety and the vehicle's performance. Ignoring this symptom can lead to hazardous situations, such as fuel leaks that pose fire risks or damage to critical components of your car. Start by checking the gas cap, as a loose or faulty cap is a common culprit. If that’s not the issue, inspect the fuel system for cracks or leaks in the fuel filter or pump, which can lead to significant problems if left unaddressed. Additionally, consider the emissions control system and exhaust issues, as these can also contribute to the gas odor. Vapor escapes from the fuel system should not be overlooked either. By promptly investigating these areas, you can mitigate risks and ensure your vehicle remains safe and reliable on the road.

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