What Causes Odors Before and After Starting the Car?
3 Answers
The reason for odors before and after starting the car is: gasoline smell, because the internal temperature has not reached the normal operating temperature when the engine is just ignited, and the gasoline does not burn completely. Methods to remove odors in the car include: 1. Place fruits with strong adsorption capabilities such as grapefruit peels, pineapples, and lemons; 2. Place white vinegar in the car, which has sterilizing and cleaning abilities; 3. Use activated charcoal to eliminate odors; 4. Remove protective films inside the car; 5. Open windows for ventilation; 6. Spray an appropriate amount of air freshener. Solutions for a car that won't start include: 1. Check if the battery is low on power and charge it; 2. Repair a damaged fuel pump promptly; 3. Check if the fuel level is sufficient and add enough fuel; 4. Check if the engine sensor is damaged.
Recently, my car also had a musty smell before and after starting. After inspection, I found it was an issue with the AC system. After five or six years of use without cleaning the evaporator, mold had grown inside, causing a bad smell every time the AC was turned on. Also, when I replaced the cabin air filter, I found it was completely covered in dust—no wonder the airflow smelled bad. It’s best to turn off the AC a bit early before parking and let the fan run for a while to reduce moisture and mold buildup. Additionally, I checked the engine bay and found a pile of rotting leaves near the firewall—clearing them out helped a lot. Keeping the car on recirculation mode for too long can also lead to odor buildup, so it’s important to switch to fresh air mode weekly for ventilation. By the way, new car plastic smell is normal and can be aired out by opening windows, but for older cars, the focus should be on checking the AC system and engine bay for odors.
Common odor issues during car repairs can be roughly categorized into three types. First, mold in the air conditioning evaporator, where condensed water accumulates in the gaps of metal fins, breeding bacteria and emitting odors when the AC is turned on, requiring professional cleaning. Second, rodents or bird remains rotting in the engine compartment, as animals may enter and leave carcasses inside while the car is parked. Third, fluid leaks, such as coolant dripping onto the exhaust pipe and evaporating to produce a sweet smell, or power steering fluid leakage causing a burnt odor. It's recommended to open the hood and check for oil stains or foreign objects while identifying the source of the smell by its direction. Short-term solutions include replacing the cabin air filter with a high-quality one, but severe odors necessitate dismantling and cleaning the evaporator for a complete fix. Avoid parking near garbage piles to reduce the likelihood of animal visits.
