Audi A3 (2017) cold air and coolant loss

[flyingninja12]

Hi everyone. I’m really hoping someone could guide me on my AUDI A3 issues. Car is 2L diesal

About 1 month ago, whilst driving on the motorway, I noticed cold air blowing through the vents, I never thought much about it and drove home. The next day I got a message saying my coolant was empty. When I tried to open the coolant reservoir cap it was extremely difficult but I managed to open it and add coolant. After the incident I was constantly checking the coolant and got the reservoir bottle replaced.

I noticed that whilst driving locally my vents would blow warmish air (passenger side was slightly cooler then drivers), on the motorway after 15/20 minutes the vents would just blow cold air. Also whilst driving local/motorway the coolant would remain consistent but would go slightly lower the next day (after the car cooled down). Recently whilst driving I smelt coolant and saw white steam/smoke coming out near the residue (car overpressurised?). Again the reservoir cap was extremely difficult to open - I think the steam is melting something.

I’ve spend £200 taking my vehicles to two separate mechanics, both have said nothing is wrong with my car having looked at it under the ramp. I spoke with another mechanic who said I need to replace the water pump. He mentioned the car has three electric water pumps which work locally but on the motorway some ‘sleeve’ is unable to rotate the water pump resulting in cold air. He mentioned it won’t be the heater matrix as if the heater matrix is blocked then it would only give cold air and not hot air when driving local and cold air on the motorway.

Also the fan on the vehicle is constantly on when I drive small local journeys. I suspect it may be the DPF regen but it could be the engine overheating.

Sorry for the long message, I just want my vehicle fixed.

Many thanks in advance

[cliffcoggin]

Where in the world are you Huzy? K is not a recognised location.

[Steve Q]

When you had the tank replaced did you have the system bled? Did you change the expansion tank cap? As seals can fail and you wouldn't know if it was leaking from there. Could there be an issue with the heater matrix? (Any wet carpets etc?)