Racer123

Just bought an Audi A6 3.0L S-line Quattro with diesel engine.
Great car except the cabin air won't heat up. The engine is running at normal temperature but no matter what heater controls I turn up, the cabin air temperature never rises.
Any ideas?

A6Gary

What year and mileage is/does your A6 have? Depending on how old it is, the heater control valve may be stuck close, which prevents the hot coolant to flow thru the heater core. If it is the valve, it is a relatively cheap and easy to replace it.

Racer123

Thanks for the reply
The car is 2012 and has 45000 miles on the clock
Is there a way I can confirm the valve is sticking before I replace it?

A6Gary

Your A6 is a C7 platform, so I am not sure if the same valve (Updated P/N 4F1-959-617-B to address problem in TSB #2013883-5) is used from the C6 platform on the newer platform. The valve should be located on the passenger side in the plenum under the cover. There are two solenoids that that control the coolant flow to the driver/passenger side of the heater core. If the outlet hoses are not hot when you have the temp set on a high temperature to heat, then the solenoids are stuck close. If the outlet hoses are hot, then you have possibly a blocked core or something else. Does the blower work? If not,then the blower module is probably bad.

Racer123

Thanks again for the help, the blower works ok but of course only blows cool air
I will have a look at the hoses as your idea sounds like it's the cause of my lack of heat problem