What Causes Odors Inside the Car?

2 Answers
ORuby
07/24/25 8:16am
The reasons for odors inside the car are as follows: 1. Plastic, rubber, and other materials: The extensive use of plastic, rubber, and other materials in car interiors means that organic solvents and additives in these materials gradually release into the cabin environment during vehicle use. This is one of the main causes of odors inside the car, especially in new cars. 2. Air conditioning filter: Many car owners report that when the air conditioning is turned on, a sour and musty smell blows in, which is quite unpleasant, but this condition usually eases after a while. In fact, this odor is a sign that the air conditioning filter needs to be replaced, as the air conditioning system has been contaminated by bacteria, leading to mold growth. Replacing the filter can alleviate the odor. 3. Evaporator: If the odor persists after replacing the air conditioning filter, the issue likely lies with the evaporator. Mold inside the evaporator causes the odor, and simply replacing the filter won’t solve the problem. In this case, cleaning the evaporator and air conditioning ducts is necessary.
Was this review help?
7
2
Share
Carvalho
08/11/25 3:57am
There are several common reasons for unpleasant odors in the car. I find the most frequent cause is food debris falling into seat crevices or under the carpet, which can develop mold and smell over time. Last week, I ate a burger in the car and didn't notice a few fries that fell - three days later, I noticed a sour smell. Additionally, the air conditioning system tends to accumulate dust and mold, especially emitting a musty odor when the cold air is on. Too many items in the car can also be problematic; I often keep sports shoes in the trunk, and the sweat odor can permeate through the seats. Smokers should also be cautious, as cigarette smoke clings to the ceiling fabric and is hard to eliminate. I recommend developing good habits: clean up any spills immediately after eating, regularly wash the AC filter, avoid cluttering the car with too many items, and maintaining ventilation is crucial.
Was this review help?
5
2
Share
Expand All
More Forum Discussions

Can I get a temporary license plate for a new car on Saturday or Sunday?

You cannot get a temporary license plate for a new car on Saturday or Sunday. The vehicle management office is closed on weekends and statutory holidays, so you can only go through the registration procedures during normal working hours from Monday to Friday. According to Article 46 of the "Regulations on the Registration of Motor Vehicles": For ordinary consumers purchasing new cars that need to drive temporarily within the administrative jurisdiction, a temporary license plate with a validity period of no more than 15 days will be issued; if temporary driving across administrative jurisdictions is required, a temporary license plate with a validity period of no more than 30 days will be issued. If the owner of the motor vehicle needs to apply for a temporary license plate multiple times, the vehicle management office shall not issue temporary license plates more than three times. To apply for a temporary license plate, the applicant must hold the unit's letter of introduction, vehicle origin certificate, certificate of conformity, and other relevant certificates (except for the letter of introduction which will be archived, the rest will be returned to the applicant), and go to the vehicle management office for processing. When applying, the starting and ending points of the vehicle's driving route and the duration of using the temporary license plate should be specified. After the administrator reviews the documents and inspects the vehicle, a temporary license plate will be issued, with the validity period and starting/ending locations specified.
6
2
Share

How to Turn On the Front Fog Lights of a Car?

"The method to turn on the car fog lights: The switch is located below the air vent on the driver's side. The middle knob controls the parking lights and low beam headlights, while the two buttons on the left side, arranged vertically, are for the front and rear fog lights—simply press them to activate. The right side controls the interior lights and dashboard brightness adjustment. The purpose of fog lights is to make the vehicle visible to others in conditions of poor visibility, such as foggy or rainy weather. Therefore, fog lights require a light source with strong penetration. Most vehicles use halogen fog lights, while more advanced models may feature LED fog lights. Fog lights must be installed below the bumper, at the lowest point of the vehicle body, to ensure their effectiveness. If mounted too high, the light cannot penetrate the fog or rain to illuminate the road (since fog is usually thinner below 1 meter), which could lead to hazardous situations. Fog light switches typically have three settings: 0 (off), the first setting controls the front fog lights, and the second setting controls the rear fog lights. When set to the first position, only the front fog lights are active; when set to the second position, both front and rear fog lights operate. Therefore, when using fog lights, it is advisable to be aware of the switch positions to ensure convenience for yourself without causing inconvenience to others, thereby maintaining driving safety."
15
4
Share

Why does the car shake violently when holding the brake in D gear?

When the car is held in D gear with the brake pressed, the transmission fluid inside the torque converter flows at high speed and is subjected to significant shear forces. If this state persists for too long, the temperature of the transmission fluid will rise. The engine, due to increased load, will inject more fuel, leading to higher fuel consumption and an increase in engine temperature. This can cause the car to shake easily. Prolonged use of D gear while holding the brake is detrimental to both the engine and the transmission. Check the quality of the transmission fluid: For automatic transmission vehicles, it is essential to regularly inspect the quantity and quality of the automatic transmission fluid. Typically, an automatic transmission service should be performed every 20,000 to 30,000 kilometers, including the replacement of specialized automatic transmission fluid (ATF). Monitor dashboard information: Develop a good habit of constantly monitoring dashboard information. While driving, always observe the dashboard for any warning lights. If the transmission fault light flashes, the computer indicates a transmission issue, which may manifest as difficulty starting, failure to shift gears, or inability to reach high speeds. In such cases, avoid long-distance driving and immediately contact a professional automatic transmission repair center for fault diagnosis. Regularly clean blockages: Ventilation and cooling are crucial. Periodically clean surface blockages on external components like the radiator and cooling fins to ensure better ventilation and cooling, thereby preventing high temperatures from damaging internal transmission components.
12
5
Share

How many kilometers can a Passat run before being scrapped?

Non-operational vehicles and operational vehicles have different scrapping periods, as detailed below: Scrapping regulations for non-operational vehicles: For household 5-seat sedans and 7-seat SUVs, as well as small and micro non-operational vehicles, there is no usage period limit. When the normal mileage reaches 600,000 kilometers, the state will guide the scrapping process. In addition to the above vehicles, small and micro non-operational passenger vehicles, large non-operational sedans, and wheeled special machinery vehicles also have no usage period limit. Common scrapping regulations for operational vehicles: Small and micro taxi passenger vehicles have a scrapping period of 8 years, medium-sized taxi passenger vehicles have a scrapping period of 10 years, and large taxi passenger vehicles have a scrapping period of 12 years. Public transport passenger vehicles have a scrapping period of 13 years, other small and micro operational passenger vehicles have a scrapping period of 10 years, and large and medium operational passenger vehicles have a scrapping period of 15 years. Micro operational trucks have a scrapping period of 8 years, light and large operational trucks have a scrapping period of 10 years. The vehicle scrapping process is as follows: The owner of the vehicle applying for scrapping and renewal must fill out and submit the "Application Form for Vehicle Modification, Transfer, Alteration, Suspension, or Scrapping" in duplicate and affix the owner's seal. The registration office will accept the application and issue a "Vehicle Scrapping Notice" for vehicles that have reached the scrapping period. For vehicles that have not reached the scrapping period, after inspection by the vehicle inspection office and confirmation that they meet the scrapping standards, a "Vehicle Scrapping Notice" will be issued. The vehicle owner can choose a qualified recycling company to dismantle the vehicle with the "Notice". The recycling company will dismantle the vehicle and take photos after verifying the "Notice". The engine must be separated from the vehicle, the engine block must be broken, and the frame (chassis) must be cut. The vehicle owner must submit the "Modification Form", "XX Province Vehicle Renewal Technical Appraisal Form", "Scrapped Vehicle Recycling Certificate", and photos of the dismantled vehicle to the vehicle inspection office for verification and signature. The license plates will be reclaimed, and the scrapping registration will be processed according to regulations. Special notes: According to Article 30 of the "Regulations on Vehicle Registration", if a vehicle is damaged and cannot be driven back to the place of registration, the owner may sell the scrapped vehicle to a local vehicle recycling company. If an operational vehicle is converted to a non-operational vehicle, it must be scrapped according to the original operational vehicle's scrapping period. According to Article 43 of the "Regulations on Vehicle Registration", after completing the transfer or deregistration of a vehicle, the original owner can apply to use the original license plate number when registering a new vehicle. The application must meet the following conditions: (1) submitted within six months after the transfer or deregistration; (2) the owner must have owned the original vehicle for more than three years.
11
2
Share

How long can motor oil be used after opening?

Generally, motor oil cannot be used after 6 months to 1 year after opening, as it will deteriorate if left open for too long. Here is some relevant information about motor oil: Oil classification: There are three types of engine oil for cars, namely mineral engine oil, semi-synthetic engine oil, and fully synthetic engine oil. Unlike mineral and semi-synthetic engine oils, fully synthetic engine oil is artificially synthesized, offering better performance and a longer usage period. Replacement notes: When changing engine oil, it is not necessary to choose a higher-grade oil. A higher-grade oil does not necessarily mean it is better for the car; only the engine oil that suits your vehicle is the best.
8
4
Share

Is it good or bad for a car to frequently drive on highways?

Driving on highways for extended periods is beneficial for the engine. The engine consistently operates at a relatively high RPM with optimal fuel efficiency, high combustion efficiency, and an ideal air-fuel ratio, which helps reduce carbon deposit formation. This is advantageous for emissions and lubrication, as well as prolonging the lifespan of the engine and transmission. When a car cruises at 120 km/h on the highway: Typically, the engine RPM ranges between 1600 and 3500. Smaller displacement engines tend to run at higher RPMs, while larger displacement engines operate at lower RPMs. Within this RPM range, the engine achieves the highest fuel efficiency ratio. The engine operates under closed-loop control, using an oxygen sensor to monitor the oxygen content in the exhaust. The engine's ECU adjusts the fuel injection based on the oxygen level to maintain the air-fuel ratio around 14.7:1, achieving optimal combustion and minimizing carbon deposits. During high-speed driving: Since the car is moving at high speed, sufficient air intake through the front ensures effective cooling. The engine can continuously operate under ideal conditions with good cooling, optimal lubrication, and the best air-fuel ratio, which is beneficial for extending the engine's service life.
11
2
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.