I live in Eastern Massachusetts and the winter is setting in. The morning temperatures are usually in the low 30s. First, It takes about 15 minutes to warm up the engine. Which I suppose is normal for the area I live in. If I don't get it warm, the van will try to stall when I hit the gas. Once I get driving, and the temperature gauge is in the middle (normal) position, I try to run the heat and nothing but cool and sometimes COLD air blows out. I have to drive at freeway speeds to get a little bit of heat and once I slow down or stop, it runs cold again. This is very unnerving being that I have two toddlers I want to keep warm. I also know that I have a slow leak somewhere underneath the van, leaking engine coolant. I don't now if this is related to the lack of heating, but it could be a clue. Luckily since its been so cold here, I haven't overheated the engine. I've refilled the radiator a couple of times. I always thought that as long as the engine was warm/hot, the heater fan should blow hot too, regardless of coolant level. I'm going to take into a shop next week to get it looked at.