I drove my 96AudiA4 2.8 quattroall winter and the heat was GREAT we had a couple warm days and i tested the AC for the first time and it worked so-so (think i need a recharge) but the other day it got cold again so i put the heat on 72 and it was only about half as warm as normal so i set it up to 74 better but i had to go all the way up to 80 to get what i used to get at 72-74. Fan works great and everything but i am wondering what happened?

I know these cars have a valve that lets in the coolant does anyone know if it is a single valve or dual value?

I am used to older Mercedes and they have a single valve so if it fails no heat but the newer ones have a dual valve system so if one fails you dont lose all your heating ability.

Any help?

 

Sounds like the valve to me too. Not sure, but I would guess its single valve.

 

start cheap n easy n replace ur thermostat. could also be a weak water pump. how many miles and when was the water pump replaced if at all?

 

It sounds more to me like you have a door sticking in the heater box.

 

I have the same problem. The Audi shop (which I don't trust that much) said it's the auxiliary water pump and they would charge $995 plus tax to fix it.
Now I'm checking it myself, just can't find where this pump can be found? I have read that the auxiliary water pumpis a common issue with oder Audis.
Does anyone know where I can find the auxiliary water pump?

Also, the shop also suggested to fix the rear main seal (small water leak) for $1604 plus tax. Supposedly the entire transmission has to be disassembled which takes about 15 hours. I find that hard to believe, especially since I have read some threads where folks claim to have the job done themselves in 2 hrs with $40 in parts...
Any comments are highly appreciated.