E 350 1 Ton Van V10-6.8L VIN S (1997)
13. Disconnect the hose clamps and remove the heater water hose.
14. Remove the water thermostat.
15. Remove the two studs retaining the heater water return tube.
16. Remove the upper intake manifold bolts, the upper intake manifold and the intake manifold gaskets. Discard the intake manifold gaskets.
17. Pull back and remove the heater water return tube. Inspect the O-rings and replace if required.