Abstract: A fuel consumption-measuring system includes a feed line, a first pump which pumps fuel from a tank via the feed line to a consumer, a fuel consumption-measuring device in the feed line, a first return line which branches off at the consumer and opens into the feed line between the fuel consumption-measuring device and the consumer, a second return line which branches off from the feed line between the first pump and the fuel consumption-measuring device which opens into the tank, a branch which leads from the feed line into the second return line, a heat exchanger, and a flow device arranged in the first and second return lines. The flow device provides an equal volume flow at an opening of the first return line into the feed line and at the branch leading from the feed line into the second return line.