I dont know if what im about to say applies to all cars, but it does to my car. Those coolant lines dont just flow when its cold, it does so all the time. It does this to burn off the crud that accumulates from the EGR valve. Unless you disable that, you will have alot of crap build up in there. The cold start valve that I thought you where talking about is on the bottom of the intake manifold and it allows extra air in until the engine warms up to raise the idle so the engine warms up faster.