A heat exchanger has at least three tubular conduits spaced apart for the flow of air between and around the conduits. The conduits communicate with inlet and outlet manifolds for the flow of a first liquid through the conduits. An intermediate conduit is located between at least two, but not all, of the spaced-apart tubular conduits, and the intermediate conduit has inlet and outlet openings for the flow of a second liquid through the intermediate conduit.