mar5den

Hi all my audi 80 heater is not working properly the side vents is working but the centre vents blows cold and the radiator dosent kick in any advice would be great

Rusty Spokes

Sound like your radiator could be plugged..time to do some checking of the radiator fan switch. Check for rust in the cooling system.

Your flaps in the heater box have probably lost their insulation too. A common problem.

mar5den

Thank you for taking the time to answer to my post the 2 vents either side work its just the centre one that dosent also I have flushed the radiator and it was a little rusty how do I fix the centre vent and would replacing the heater switch fix the fan

Rusty Spokes

You have manual controls on the HVAC? If your is a regular control with *****, the flappers inside the heater box lose some insulating foam on them and then don't direct the air to the center vents..don't know if the hot air is deflected up to the outside vents..maybe..don't know for sure.

A picture of my heater box flaps when I repaired my B4 Cabriolet..the heater was a mess and very cold...may be the same on the Audi 80.


The heater core was replaced at the same time..even though it gave off some heat..it was plugged up. The OEM Behr heater core as those twisted swirlers inside the tubes and they get plugged up easily. Might as well do it when the dash is out.




Be sure your cooling system is bled of all the air prior to doing the big work..an air pocket will form up the top and the heater will not get enough coolant to work. Here is a write up on bleeding an A4..same deal on the 80..except you only have the fitting up at the heater hose..which can be delicate and crack..so be gentle..and mark the closed position of the screw then count the number of turns you make to open it..run the engine and rev it slightly with the cruise control diaphragm. Close the screw when the flow is all coolant with no air bubbles and the engine is warmed up..counting back the same number of turns so you don't break the plastic..thermostat should be open while bleeding. An air pocket might explain your radiator fan problem too. Bleed the system and see.

Proper way to bleed a 96 A4 2.8 12v cooling system? :: motorgeek.com