Need a diagram of coolant circulation . Can i ask if anyone can tell me whats wrong with the heater system in my friends car a W124 260E. no aircon model . All heater hoses are hot. The vent pods all open up,, and close as normal . We find blown air in the footwell to the driver side is hot . But the passengers footwell is cold .. Heater pums good DV valve is working ok Thanks for any help you can give on this one .