- Fig. 1 Overview of instrument cluster
The coolant temperature gauge -1- Fig. 1 only works when the ignition is switched on. In order to avoid possible damage to the engine, please read the following notes for the different temperature ranges.
Engine cold
If the needle is still in the lower range of the dial, this indicates that the engine has not yet reached operating temperature. Avoid high engine speeds, full acceleration and heavy engine loads.
Normal temperature
In normal operation the needle will settle somewhere in the centre of the dial once the engine has reached operating temperature. The needle may also go further up when the engine is working hard at high outside temperatures. This is no cause for concern, provided the warning lamp 
does not light up in the instrument cluster.
does not light up in the instrument cluster.If the needle is at the top end of the dial, this means the coolant temperature is too high. In addition, the warning lamp Link will light up.
Link will light up.Caution!
- Additional lights and other accessories in front of the air inlet reduce the cooling effect of the radiator. At high outside temperatures and high engine loads, there is a risk of the engine overheating.
- The front spoiler also ensures proper distribution of the cooling air when the Audi A4 is moving. If the spoiler is damaged this can reduce the cooling effect, which could cause the engine to overheat. Obtain professional assistance.
Note
Diesel engines are so efficient that they may not reach their full operating temperature in very cold weather. This is quite normal and no cause for concern.