See also:

REV indicator light (STI)
This light illuminates when the engine speed reaches a level set by driver or when the tachometer needle enters the red zone. ...

Lubrication oil circulation in the refrigerant circuit
Operate the air conditioner compressor at a low engine speed (at idle or low driving speeds) a few minutes each month during the off-season to circulate its oil. ...

Tachometer
The tachometer shows the engine speed in thousands of revolutions per minute. Do not operate the engine with the pointer of the tachometer in the red zone. This may cause severe damage to ...