In most Audi A4 models, the main engine oil drain plug sits on the bottom of the engine oil pan, accessible from underneath the car. There are also drain plugs for the cooling system and the transmission, and exact locations can vary by generation and engine code.
Across the A4 lineup—from older B5 models to newer B9s—engine bays and pans differ, so the precise spot for each drain plug depends on the exact engine variant. Always consult the owner’s manual or a factory service manual for your year and engine code to confirm the locations and torque specs.
Engine oil drain plug location
The engine oil drain plug is typically located on the bottom of the engine oil pan. It is accessible from underneath the vehicle when it is properly lifted and supported. The bolt head is usually a standard hex or socket size, found toward the front or side of the pan depending on the engine design.
- Engine oil drain plug: bottom of the oil pan, accessible from underneath the car.
After draining, reinstall the drain plug and refill the engine with the correct oil type and quantity, following the manufacturer’s torque specification for the drain bolt.
Transmission drain plug location
Both automatic and manual transmissions used in the Audi A4 have a drain plug on the bottom of the transmission pan. Access is from beneath the vehicle, with the car in a safe, level position. Some models may require draining the transmission pan and rechecking fluid levels after refill.
- Automatic transmission drain plug: bottom of the automatic transmission pan, used to drain ATF.
- Manual transmission drain plug: bottom of the manual transmission pan, used to drain gear oil.
Reconnect and refill with the correct transmission fluid or gear oil as specified by Audi for your model year and transmission type. Dispose of old fluid responsibly and, if you’re not experienced, have a professional perform the service.
Coolant drain plug location
The coolant drain is usually found at the bottom of the radiator or via a drain plug/valve on the engine block or heater core circuit, depending on the engine family. Draining coolant requires caution as the system may be pressurized when hot; never open while the engine is hot.
- Coolant drain valve or plug: located at the bottom of the radiator or along the engine cooling circuit, depending on model.
After draining, flush if directed by the service manual and refill with the correct type and concentration of coolant. Bleed the cooling system as required to remove air pockets.
Locating the exact drain plugs for your model
Because Audi uses multiple engines across generations, the precise drain plug locations can differ. Use your vehicle’s VIN or engine code to pull the exact diagrams from the factory service manual or an accredited repair guide. A quick undercar inspection can help identify the obvious drain points, but always verify with documentation to avoid damaging components.
Safety tips and best practices
Always secure the vehicle on level ground and support it with jack stands before going underneath. Let the engine cool before draining engine oil to avoid burns. Use the correct drain plug size and a new washer if required, and never over-tighten. Proper disposal of used fluids is essential; take them to an authorized recycling facility.
Summary
The primary engine oil drain plug for an Audi A4 sits on the bottom of the engine oil pan, but there are additional drain plugs for the transmission and coolant that vary by generation and engine. Always verify the exact locations for your specific model year and engine code in the owner’s manual or a factory service manual, and follow all safety and disposal guidelines when performing any drain or fluid change.