Lord Craft

I take photo of rubber pipes not brake fluid reservoir
the pipes are cold all the time.

jfrahm

Did you ever try the suggestions for getting coolant to flow to the heater core?

Lord Craft

no i didn't, how I can do that?
I just check hvac pump
make some vdcs tests
flush both saloon radiators
and bleed air out.

Lordcraft

Im so lost with this problem. Even mechanics doesn't know where is the problem...

I did change timing belt with all pumps and thermostat.
I did change this unit twice! There is no air in the system for sure.

For example if I go shopping for 10mins and come, I have heat for few minutes and again cold air blows

Who is controling this all mechanizm? Raley? Fuse? Comfort block?
Maybe someone have VDCS guide? Im total noob with VDCS...

nw-indiana

It is very odd that there is heat on occasion, but not often. Later cars have a control valve that shuts off the flow of coolant, but I don't recall seeing one on the D2.

Getting to the basics - if the heater hoses to and from the heater core are cold, the hot coolant is not flowing through the heater core.

I would first isolate the issue between the heater core and the cooling system by connecting those two hoses with a copper U and driving until the engine is warm.

If the hoses and the copper get hot, then the heater core is plugged and needs a thorough flushing with citric acid or replacement.

If the hoses do not get hot, then the water pump is not circulating coolant, and things get more complicated. (This should absolutely not be the case.)

jfrahm

Old thread where someone had to replace the heater valves/pump assembly to get heat:
https://www.audiworld.com/forums/a8-...-heat-2818957/

No flow though the heater cores, stuck heater control valves it sounds like.