Needle position at different temperatures

Fig 1: Identifying Needle Position At Varying Temperatures

Courtesy of VOLVO CARS OF NORTH AMERICA.

This adjustment is always carried out on a cold engine. 

A suitable temperature is approximately 20°C/68°F  .

At higher temperatures, for example with engine at operating temperature or at higher ambient temperature, the indicator is further to the right.

The illustration shows the needle position when adjusting the camshaft belt tensioner at different engine temperatures.