Question about Audi A4
Your going to have to get under the dash and inspect the heater doors. The door you hear opening and closing is a center door, there is also a temp door that is not activating. Both doors are controlled by a cable and the doors are in a housing assembly in the dash (big job to remove)
If the mechanic back flushed the heater core, than it is good. Otherwise, it the heater core was clogged, you would not be able to back flush it. I have posted some illustrations to guide your repair.
Center door lever
Posted on Jan 04, 2011
Have you tried flushing the heater core? Check and re-check radiator for any partial clogged, also check thermostat.
Flush the heater core really good, then refill coolant and make sure you get all the air out. Drain the coolant, disconnect the 2 hoses on the firewall and flush in both directions with a garden hose. It would be nice to put a spare piece of hose on each connection to make it easier and not make a mess of the engine bay, but whatever you have to do.
I do not believe there is a water valve of any kind for the heater core. This document has some directions on draining and filling the coolant and bleeding the air out: A4-S4_B5/Engine/19-1 Cooling system components.
Hope helsp. Keep us updated.
Posted on Jan 03, 2011
There is a control valve under the hood, if it doesn't open no water gets to the heater core on the inside of the vehicle. There should be 2 water lines that connect from the engine back tot eh firewall. They are about 3/4" in diameter and normally on the top one there is a valve that is either vacuum, wire or electrically controlled. If that valve doesn't open you have no heat. Since it is winter and you may want to fix the heat now and worry about fixing that valve later you can remove that and replace it with a piece or straight pipe. If that valve is working correctly the problem maybe your thermostat not opening or your water pump not circulating correctly however in most cases if either of those was the problem the vehicle will be overheating.
Posted on Jan 03, 2011
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Posted on Jan 02, 2017
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