Heating output as a function of engine speed

Hi,

'Although this is about a gasoline engine, I don't think that will be a problem in this context.'

Start the engine, everything is fine (temperature 90 degrees), warm air is coming out of the nozzles.
You drive past a traffic light (or the McDonald's switch) and after a short time, the heater starts blowing out increasingly colder air, getting colder and colder.

SOBALD, however, once you restart the engine (or start it up again), after a short time, warm air will again come out of the nozzles.

WHAT IS THIS??

New are now:
- Thermostat housing (characteristic cooling) with thermostat and coolant temperature sensor
- Water pump
- Sender for water temperature at the outlet of the cooler

When the pump arrived (yesterday), we tried blowing air into the heat exchanger (in different directions) and it always came back out on the other side as a thick jet of air, or, in the first attempt, as a thick spray of water.

The control value of the temperature control valve changes whenever you take your foot off the accelerator or press the accelerator again.

I also have some funny logs where you can clearly see it.

KANN it be the control panel???

I'm really struggling to move this box slowly.

Okay, is a 2002 Audi A3 with a 1.6-liter gasoline engine.

The fact is, the coolant temperature remains consistently between 87 and 93 degrees, and the thermostat doesn't unnecessarily open (the sensor on the radiator remains cold) - it only opens when it's supposed to, and you can immediately see this by checking the corresponding MWB (measurement/display unit) via the sensor on the radiator.