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.
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.
There are many reasons why your Mercedes-Benz E400 smells like gas as you drive. Gasoline is extremely volatile, which is why gas vapors spread quickly and you can easily smell a leak in your car. Many components of modern fuel systems incorporate seals and o-rings that can decay over time. The most common sources of leaks can be the fuel pump, fuel filter, and fuel injectors, but also emission system components. Smelling gasoline may indicate that your vehicle is not running efficiently or getting the best mileage. More importantly, long-term exposure to gasoline fumes is deadly and can damage your lungs - meaning that this symptom is not just bad for your wallet, but also your health! For all these reasons, anything that causes your Mercedes-Benz E400 to smell like gas should be repaired right away.
In many situations your Mercedes-Benz E400 smelling like gas will not result in a fire hazard, it is still important to have the severity determined and the problem resolved. Gasoline fumes are toxic and can result in carbon monoxide poisoning. Your Mercedes-Benz E400 smelling like gas could signal a gasoline leak which can present a significant fire hazard. Fuel leaks can be hidden in the engine bay and in the undercarriage and may not present themselves as fuel on the ground as gasoline can evaporate quickly. It is best to not drive your Mercedes-Benz E400 or park it in an enclosed space like a garage. Contact a RepairPal Certified service location immediately for more advice, and prepare to have your car towed. If it appears to be a significant leak, with a noticeable amount of gasoline dripping out of your vehicle or if the smell of fumes is intense, call your local Fire Department.
The technician will first check for a gasoline leak, which would be the most dangerous scenario if your Mercedes-Benz E400 smells like gas. The fuel tank, fuel lines, fuel injectors, and other relevant parts of the fuel system are checked for any obvious signs of leaking. Fuel and emission system components can leak fumes as well as liquid fuel. The source of leaking fumes can be determined through a vacuum pressure test, depending on the fuel system. In certain engine configurations, valve clearances may need to be checked. If valves in the engine are not closing properly, unburnt fuel can be sent into the exhaust system, causing a gas smell.
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