Going into the red area is considered over revving.
All vehicles with an internal combustion engine are fitted with some kind of rev limiter that prevents the engine from revving beyond its physical capacity. Reaching this limit from time to time is okay, but abusive driving can cause damage.
The electronic rev limiter controls the engine speed via the vehicle’s on-board computer. The manufacturer determines how high the rev limit, or “redline,” should be. Reaching this limit from time to time increases wear and tear on your engine, but will not damage the vehicle. The limit is measured in RPM (revolutions per minute) and is denoted by the red line on your tachometer.
Reaching the rev limiter without switching to the next gear will cause a bouncing effect–what people refer to when they say “bouncing off of the limiter.” This has the potential to damage the engine, despite the fact that it is technically running within safe operating speeds. Also, abusing the vehicle by racing or driving hard will increase the likelihood of damage.
Consequences for hitting the rev limiter typically include increased engine wear and oil burning. Worse cases, though, can include engine overheating and ceasing. When this happens, rods can be bent and head gaskets can be blown, which will most likely permanently damage the engine.