‘16 Q50 Red Sport - After the Turbos were replaced by the dealer, later that evening I noticed smoke coming from under hood and could smell coolant. Videoed and sent to dealer. Took back to dealer for inspection. Dealer confirmed, not new Turbos. Dealer said coolant was low filled coolant. A few days later - heat quit blowing warm air. Dealer said coolant was low filled coolant and replaced heater hose due to pinhole in heater hose. A few weeks later, heat quit blowing warm again. Dealer found oil was contaminated with coolant. Replaced the long block. Now, ~2K miles later - O2 sensor bank b and catalytic converter have failed. Should the sensors and the converter have been replaced at the same time as the long block? With coolant leaking into the oil, could coolant have burnt in the combustion chamber causing contamination in the O2 sensor resulting in a rich fuel mixture and clogging the catalytic converter?

No smoke no leaking ,plenty of fluid. turning on the heater doesn’t help, when the car is in motion or at a regular speed. The gauge drops to average temperature but sitting at a light or accelerating causes the gauge to rise.. car still blows cold air and heat when using cabin temperature settings. No noises or smell. Temperature gauge rises to maximum within 2 blocks of driving. Infinite q50 2015. I previously had this problem before in the winter and it only happened twice, but then it went back to normal and it hasn’t done it for a few months and now it’s doing it again in the summer but it has been over 100° outside so I didn’t know if that had something to do with it. I was believing that maybe my thermostat was stuck in the closed position, but I don’t want to spend the money and have my boyfriend fix the thermostat if these problems seem to be related to something else