I replaced the radiator, water pump and thermostat. As part of the process we obviously drained the system. Once it was all back together, we refilled with coolant mix. The problem is that it only took about 12 quarts of coolant, well below the fill quantity. I have driven it several times since and the temp has not risen beyond normal. In addition, the fluid levels have not dropped from the level it was filled to originally. Are there any things I should be looking for? Or is there anything I can do to ensure the system is properly filled? Thanks.