Spark Plugs

Spark plug designations

Using the designations in the table below, you can select spark plugs suited to your vehicle. What do the numbers and letters mean?

Heat range: spark plugs must be designed for the temperatures generated during combustion in the engine. The heat range indicates how much heat the spark plug can dissipate without overheating itself. If the spark plug dissipates too much heat, it does not reach its self-cleaning temperature, and soot deposits form on the electrodes.

Electrodes: the Audi 80 uses spark plugs with three electrodes.

Thread: the thread length for Audi 80 spark plugs must be 19 mm; thread diameter is 14 mm.

Wrench size: the hexagon for the spark plug socket must be 20.8 mm across flats on 4- and 5-cylinder models; on 6-cylinder engines this dimension is 16 mm.

Seat: all engines require spark plugs with a flat seat. They are fitted with a captive sealing washer, so no additional sealing washer should be installed.

Tighten the spark plugs to a torque of 20 N·m. If a torque wrench is not available: screw the plug in until the sealing washer contacts the seat (arrow), when it can no longer be turned by hand or with the spark plug socket without applying force. If you have installed new spark plugs, then tighten them with the spark plug socket by approximately another quarter turn. If you are installing used spark plugs, turning the spark plug socket by another 15° is sufficient.

Spark plugs for Audi 80

The spark plugs listed in the table comply with the manufacturer's specifications.