Coolant Pump v50 open circuit

Hi

Hi I started this topic because I could not find the answer in relation Coolant pump V50 "what is wrong". I own Audi A8 3.0 TDI, and couple weeks ago I changed thermostat because temperature was too low while driving car even 30 miles from start cool engine.
I had I hope that everything will back to normal, unfortunately no.
While driving in the city temperature is almost 90 degrees, driving on the motorway is dropping down to 75 degrees even less using heating system. I do not really know where to looking a solution. While doing a test in Audi one error show up V50 Coolant pump open circuit, is this possible that this pump has something to do with engine temperature? Please give me some advice what to do.

AFAIK V50 is under the cover below the windscreen and helps the water flow though the heater matrix at low RPM or when engine is off (residual heat)
I doubt it is your cool running which is more likely to be the secondary thermostat which is hidden beside the autobox....

Running cold issue. Tricky one-thoughts needed - A8 Parts Forum

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Originally Posted by Raflus

Hi

Hi I started this topic because I could not find the answer in relation Coolant pump V50 "what is wrong". I own Audi A8 3.0 TDI, and couple weeks ago I changed thermostat because temperature was too low while driving car even 30 miles from start cool engine.
I had I hope that everything will back to normal, unfortunately no.
While driving in the city temperature is almost 90 degrees, driving on the motorway is dropping down to 75 degrees even less using heating system. I do not really know where to looking a solution. While doing a test in Audi one error show up V50 Coolant pump open circuit, is this possible that this pump has something to do with engine temperature? Please give me some advice what to do.

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Thanks alot Bro this is brilliant, Ordered today new thermostat :)
Gearbox thermostat changed, everything now had come back to normal.