Coolant temp seems to dip slightly when using heater?

[BraveUlysses]

I recently tore apart a good portion of my 318iS to replace most of the gaskets and remove the "mess under the intake manifold."

In doing so, some coolant drained out of the block but I topped it all off after putting everything back together...car drives fine, heats up like it should but it seems that when I turn on the heater (it still blows hot) the temp gauge moves a slight bit away from the middle mark...which I don't recall it doing before (but I only drove it 5 days before tearing it all apart to fix everything, so I'm not sure how it should behave).

Is this normal? Or maybe due to the fact I didn't bleed the cooling system?

[Jordan325iC]

It would make sense that turning on the heater would cause a very slight shift in coolant temperature, since that it just one more outlet for heat to escape from the coolant. I don't think you have a problem.

[Doughnut]

It would make sense that turning on the heater would cause a very slight shift in coolant temperature, since that it just one more outlet for heat to escape from the coolant. I don't think you have a problem.

+1.

I have used my heater to cool the temperature of the engine in stop go traffic a couple of times, pointing at the windscreen with fan on full of course.