You are correct,there are several things that will effect the amount of heat thrown.Start with the coolant improper levels or diluted mixture will effect it.A bad thermostat (stuck open) or a bad temp control valve will effect heat. A stuck blend door (that mixes hot and cold air) will effect it.These are the most likely causes.The first couple are easy to check.The blend door get a little more difficult.Check it out and let us know and we'll help you further.
PV
PV
