There could be several reasons why your Fiesta ST oil smells like gas. Here are a few possible causes:
1. Fuel Contamination: One possible reason is that there is fuel contamination in the oil. This can happen when there is a problem with the fuel injectors or the fuel pressure regulator, causing excess fuel to leak into the combustion chamber and mix with the oil. When this happens, the oil can become diluted with gasoline, giving it a strong gas smell.
2. Engine Misfiring: Another possible cause is engine misfiring. When the engine misfires, the fuel may not be fully combusted, leading to unburned fuel entering the combustion chamber and mixing with the oil. This can cause the oil to smell like gas. Misfiring can be caused by various issues, such as faulty spark plugs, ignition coils, or fuel injectors.
3. Rich Fuel Mixture: If the fuel mixture is too rich, meaning there is too much fuel in the air-fuel mixture, it can lead to incomplete combustion and fuel entering the oil. A rich fuel mixture can be caused by a malfunctioning oxygen sensor, a faulty fuel pressure regulator, or a clogged air filter. This can result in an oil smell of gas.
4. Engine Flooding: Engine flooding can also lead to gas smell in the oil. Flooding happens when the engine gets too much fuel, which can overwhelm the combustion chamber and cause fuel to leak into the oil. This can occur if there is a problem with the fuel injectors or the engine’s computer system.
5. Fuel Line Leak: A fuel line leak can also cause gas to enter the oil. If there is a crack or hole in the fuel line, it can result in fuel leaking and mixing with the oil. This can lead to a strong gas smell in the oil.
6. Vaporized Fuel: In rare cases, the gas smell may be caused by vaporized fuel entering the crankcase ventilation system. This can happen if there is a problem with the PCV (Positive Crankcase Ventilation) valve or if the engine is running at a high temperature, causing fuel to vaporize and enter the oil.
If you notice that your Fiesta ST oil smells like gas, it is essential to address the issue promptly. Gas contamination in the oil can lead to various problems, such as reduced lubrication, increased wear and tear on engine components, and decreased engine performance. Furthermore, continued use of gas-contaminated oil can result in serious engine damage.
It is recommended to have your vehicle inspected by a qualified mechanic or technician to diagnose the cause of the gas smell in your oil accurately. They will be able to perform the necessary tests and inspections to identify the underlying issue and recommend the appropriate repairs or maintenance. Diagnosing and resolving the problem promptly can help prevent further damage to your engine and ensure the continued reliable operation of your Fiesta ST.