It is way too expensive to replace the heater core in this car.
Audi a4 b7 heater core flush.
2007 b7 audi a4 2 0l alt cooling system service including coolant flush.
Now is probably a good time to drain flush and bleed your whole cooling system.
Reverse the hose and forward flush again making sure the water coming out is clear.
How to flush a heater core safely with a garden hose duration.
Turn on the water flow not too hard as the heater core is a bitch to replace and watch the gunk come out.
Flush the heater core on an a4.
Keep flushing until the water coming out is clear.
Cleaning heater core and bleeding 98 audi a4 b5 aeb 1 8t.
How to replace the rear coolant flange and heater hoses on a 2004 2008 audi a4 b7 2 0t.
My 2001 audi a4 had no heat due to a plugged heater core.