The heater in my 1998 VW Passat sedan is not providing any heat to the passanger compartment. I checked the cables on the dash control and they are connected and make door noises when moved. The fan is working. I replaced the engine cooling system thermostat and bled the cooling system hose at the heater core per the repair manual.
Does the Passat have a Pass Valve? Or could there be another problem. All previous service was at a dealership.
Usually there are two ways the heater systems work.
One - The heat from the engine is regulated through a valve that is opened by vacuum, cable or motor. This opens the valve allowing hot coolant to flow through the heater core.
Two - The hot fluid continuously flows through the heater core in a plenum. The plenum is thus usually hot and awaits the door to open to let out the heat.
You mentioned that the cables appear to be fine. Doesn't your repair manual show a valve? I don't have access yet to a maintenance manual on that model.
January, 8, 2007 AT 10:26 AM
The 1998 Passat does not have a valve between the engine and the heater core, or so I have been told by the VW repair technicians at the local VW dealer. I think I am looking at a new core because they have a tendency to plug up. Heater core replacement requires removal of the entire dash board and instruament cluster which is beyond my capability.