What causes a foul smell inside the engine?
3 Answers
If there is a foul smell inside the engine, you can have it repaired at a 4S shop. The odor in the engine may be caused by a plastic smell or a malfunctioning air conditioning system. Burnt plastic smell: If you detect a burnt plastic smell, it is mostly due to overheating of some electrical wiring in the car. When wires burn out, they usually exhibit localized heating or smoking. With careful inspection, it should not be difficult to identify the source of the issue or the faulty components. Air conditioning odor: The main cause of air conditioning odor is that the AC system provides the three key conditions for mold growth (warmth, moisture, and a nutrient source). Over time, these stubborn contaminants cause the vehicle's evaporator to become a breeding ground for bacteria and mold. As a result, every time the AC is turned on, these bacteria and mold are blown into the cabin with the airflow and can be inhaled by passengers, leading to adverse reactions such as headaches, fever, sudden sore throat, tonsil infections, asthma, flu-like symptoms, dermatitis, and slow wound healing. In severe cases, it may even cause dizziness, chest tightness, and other discomforts.
I've been driving for decades and have encountered many cases of engine odors. Common causes include oil leaks or burning, which smell like burning oil smoke. Or coolant leaks, which have a sweet odor, like syrup. Electrical short circuits or overheating produce a burnt plastic smell. Fuel system leaks give off a pungent gasoline odor. Problems with the air conditioning system can produce a musty, damp smell. Safety first—if you smell an unusual odor, stop the car and turn off the engine to avoid burns while inspecting a hot engine. Check the ground for signs of oil or fluid leaks. Judge by the smell: a sweet odor often indicates a coolant issue, while a burnt smell points to wiring problems. Visit a repair shop promptly for diagnosis—don’t wait for a minor issue to escalate into a fire or engine damage. Regular maintenance can prevent most odor sources; inspect oil lines and wiring at least every six months.
I must remind everyone to handle the smell from the engine with caution. The most common scenario is burning engine oil producing a thick smoky odor, or coolant leakage emitting a sweet smell. Overheated wires burning with a plastic-melting odor is also very dangerous. Fuel leakage brings a strong gasoline smell. A musty odor from the air conditioning system usually indicates a dirty evaporator. If you notice any of these smells while driving, stop immediately and turn off the engine. Open the hood but wait for it to cool down before checking for leaks or burn marks. You can preliminarily check if the fuses are intact. Different smells point to different issues: a sweet smell indicates cooling system problems, while a burnt smell suggests electrical issues. Do not attempt to fix complex problems yourself; drive directly to a professional shop to avoid causing further damage. Regular maintenance with quality engine oil and antifreeze can prevent these issues.
