Have the same problem. It's the heater core. Can almost guarantee it!
January, 26, 2006 AT 7:36 AM
Could also be another couple of reasons. You have air in the heater matrix which needs bleeding or you have a blockage in the matrix itself. Remove heater hose from one side of the matrix and connect a hose pipe to it and flush out. As for the air pocket: - disconect hose from return side of the matrix whilst engine running and wait for hot water to come out or look for a bleed screw on the hose