A heat exchanger including a heat exchanger block having first fluid channels and second fluid channels, including a fluid collector, the first fluid channels having a first fluid channel section and a second fluid channel section. A first fluid inlet is provided, which is fluidically connected to the first fluid channel section of the first fluid channels. A first fluid outlet is fluidically connected to the first fluid channel section of the first fluid channels. A second fluid inlet is fluidically connected to the second fluid channel section of the first fluid channels. A second fluid outlet is fluidically connected to the second fluid channel section of the first fluid channels. The fluid collector has a third fluid inlet, a third fluid outlet, and a fourth fluid inlet, which is fluidically connected to the second fluid channels. A fourth fluid outlet is fluidically connected to the second fluid channels.