Does your coolant temp drop when you turn the heater on max?

[SparkYellow]

One thing that I have learned after a cooling disaster on my MINI is that by turning on the heater, the coolant in the heater core gets to mix with the rest of the fluid and helps bring down the temperature slightly.

Now that I am watching the temperature of the CX-3 more closely, I tried this and nothing happened. By turning the heater on max (max temp and fan, nothing sophisticated on my Touring). After five minutes of running like this at 65-75 mph, the coolant temp continued to fluctuate as if the heater was off. The heater was blowing hot though. Is this normal?

I am 80% positive that I tried this once last year and the temp went from 212 to 190 in stop and go traffic. There is a 20% chance that my memory failed me and that it was in the MINI.

Any insights are appreciated.

 

[Buzzman12]

A lot of this has to do with the size of the engine.
In my experience (60 years driving), a larger displacement engine will maintain the engine temperature regardless of the heater settings. Lately however, this trend towards small displacement engines, and smaller coolant capacities, puts a little more strain on the cooling system, having to keep the engine at a steady level, while also delivering enough warm coolant to the heater core to warm the interior.
I know for a fact that the Honda 1.5L turbo CR-V has issues in cold weather. The engine takes forever to heat up, and the cabin heater and defroster drain any heat that might have built up from the engine. My brother in law had one of these, and it was brutal in our Canadian winters. You could let this thing idle for 20 minutes, and it would still be stone cold.
I don't know the particulars with some Mazda models (my 2017 Mazda 6 was fine), but I imagine any small capacity engine will have similar issues.