Hey,
I've got a weird engine cooling problem. When I first got the car it would take forever to get the coolant to optimum temperature and it would overheat when stationary/start-stop traffic and would drop down below half of the coolant temperature gauge's scale. I thought it's a thermostat so I've replaced that for brand new one and now it won't overheat when stationary, it stays rock solid in the middle of the scale and heats up a bit faster (but still a bit slow imo) although when I drive about the temperature still drops. In normal cruising situation (30-70mph) It will oscilate between 1/4 and 1/3 of a scale. When I boot it and rev it up high couple of times the temperature stabilises a bit more but it's still around 1/3 of a scale.
On top of that, weirdly the heater inside the car gets warm pretty much straight away. In my 2000 Mazda, and in fact any other car I've ever been in, the heater will blow cold for ages until the engine gets up to temperature. In my Civic it blows cold very briefly and gets nice and warm pretty much straight away.
What could be the problem? Or is this how it is supposed to work?
Cheers!