I have a 1997 A6 Quatro with a heat problem. The engine temperature shows plenty of heat, but the heat coming out of the defrost and/or cab heater is very cool. Not much heat at all.

No leaks around the heater core as I have read. My guess there is a valve of some sort that allows coolant threw the heater core that might not be opening completely?

Just a thought thou...

Any tips?

Oh the system has plenty of coolant too.. and the car has the "climate control" too which Ive checked all the fuses for.

Kind Regards..

Eric

 

A couple of things to consider:

You didn't indicate what year A6 - mine is a C5 - at the fire wall next to the battery is where the inlet and outlet for the heater core. On the C5 the top hose is the discharge. After the car is at operating temperature, is the top hose (return) hot? If not there may be blockage in the core. The core can be back flushed fairly easily.

I back flushed mine and still had no heat. It turned out when I checked VAGCOM for codes my climate control unit had failed. Replaced the unit with a used unit for about $60 and now heat works fine.

VAGCOM will allow you to check the control unit and all the system “doors” for function.

 

oops sorry its a 1997...

I bought a VAGCOM cable but not sure what software to get from Ross-Tech: Home..

I found the hoses under the wiper compartment going into the cab area, Bottom is 120 degrees, top is 60 ish degrees, My guess is the core is clogged.

Back flush looks really hard...

 

Here is what I did to back flush:
My local hardware store had ¾ inch (check your connection size – 7/8 in. may work better) clear plastic flexible tubing which I bought ten feet of and cut in to unequal lengths. I had to remove my battery to get at the heater core connections. The longer length I connected to the intake side of the core and draped that on to the ground. I connected the shorter length to the return side. I poured in some CLR as recommended by a mechanic friend through the return side (you want to flush backward to the normal flow) and let it sit for a bit. I then used a garden hose with a nozzle (we have pretty good water pressure) and flushed until it was clear. Then I blew the water out, reconnected and bled the system.

To bleed the system the top or return hose should have a small hole. Pull the hose back far enough to allow coolant to come out the hole. Get a funnel that fits the coolant recovery tank and pour G12 in until it comes out the small hole in the hose. Slide the hose back on and tighten clamp.