Originally Posted by
joshofalltrades
i recently ADDED rear heat to my e350. i thought about running metal lines, but for convenience i just went with a long piece or heater hose. the second heater is just behind the drivers seat, is on a totally seperate circuit from the front heat, and has about 17 feet of hose in the circuit. its connected to a previously unused port on the waterpump and a previously unused port toward the rear of the left head. even with all that 5/8" hose, it puts out quite well!