In the traffic jam, the heating stops and the engine gets hot? (188)

Hi, what’s going on in the hot water cycle? When the hot water cycle was busy I had a nice time in the hot water cycle (was a thick police check at the main traffic time :/) The heater was already warm, stop-and-go? And then there was no hot air out of the heater and the radiator fan went on in between. So it went on for a while while while I was thinking about whether I had a cooling circuit leak or the water pump is giving up the mind. Water didn’t run out (it went out and looked at it) and every time I gave a few seconds gas, it got a bit warm. When the car stopped again cold. Behind the traffic jam the heater immediately got warm again (it was a tempo 70 distance). That fits to the small abnormalities of the last few weeks, the temperature indicator fluctuated from time to time (it went a little bit higher). It also felt a bit longer, until the car was warm and then the car didn’t get warm again.