If it takes a while for the heater to come on, then it's most likely your thermostat.

Other potential causes of overheating:
-headgasket
-radiator cap
-leaks in hoses leading to low coolant level
-wrong mixture/type of coolant
-water pump

I fail to see that it's your water pump, but then again I don't know your car. When you park it, have it running and check for leaks. You can also make sure that all air is out of the lines.

Look here: https://www.honda-acura.net/forums/s...threadid=30487