Causes of Odor

Causes of Odor

• Smells like burnt oil.

- Mostly forms in the engine compartment due to leaks on the engine or transmission.

• Sulphurous smell similar to exhaust.

- Due to leaks in the exhaust system.

- Through exhaust fumes, which get into the passenger compartment, for example, when driving in reverse through an exhaust gas cloud.

• Fishy smell like coolant.

- From leak at cooling system of engine or of A/C system heater core.

• If fishy odor occurs depending on temperature setting (weaker with temperature setting "Cold" than with temperature setting "Warm"), check A/C unit heat exchanger for leaks (air does not flow constantly through heat exchanger).

• Smells like a burned clutch.

• Evaporation from floor mats, decorative seat covers, etc.

• Rotten, mildewy, moldy or musty smell from plenum chamber.

- Due to various contaminants, such as leaves, pine needles, etc. collecting.

- Due to water that cannot drain out of the plenum chamber.

• Check plenum chamber water drains. Refer to=> [ Plenum Chamber Water Drain, Checking and Cleaning ] Service and Repair.

• Smell from air conditioner.

• Odors originating in the heating and A/C unit can mainly be detected in fresh air mode and recirculated air mode. If a smell occurs only in fresh air or recirculation mode, the cause is probably not the A/C unit.

• In the case of a leaking heat exchanger, the odor of the escaping coolant mostly depends on the temperature setting. With "Cold" temperature setting, air does not flow through the heat exchanger and the odor is not as strong.

- Due to too much condensation water in A/C unit.

• Check condensation drain. Refer to=> [ Condensation Water Drain Hose, Checking ] Testing and Inspection.

- Due to an old or heavily contaminated dust and pollen filter.

• Check dust and pollen filter. Refer to => [ Dust and Pollen Filter ] Service and Repair.

- Due to deposits on evaporator fins.

• Clean evaporator with Ultrasound A/C Cleaner (VAS 6189). Refer to=> [ Evaporator, Cleaning with Ultrasound A/C Cleaner ] Evaporator, Cleaning With Ultrasound A/C Cleaner.