To crank up is an informal phrasal verb meaning to increase something or to make something more intense especially when talking about volume. To crank up can also mean to invigorate or energise or to inject a narcotic drug. To crank up can also mean to start something mechanical.

1. I couldn't hear the radio from the other room, so I asked my brother to crank up the volume.
2. Once a month my father cranks up his old car and we take it for a drive together.
3. The weather is getting much colder it's time to crank up the heating in the house.

1. With the deadline looming, that setback has really cranked up the pressure on us to deliver on time.
2. Staff have not been pulling their weight recently. They need to crank it up a notch.