Quote Originally Posted by Simi Mike View Post
Yes, both are under pressure. My tubular overflow, has a pressure cap on it. But it doesn't have anything in it ! I was going to put a cup full of radiator fluid in, and check it again, after it cools down - - - next time I go out. Its raining in So. Cal right now. Thanks again Dave and Jerry.
Nope, that's what the second tube is for. Let's the pressure out! If it was a sealed container, nothing would be allowed in! The second tube should be within an inch or so of the top (generally..) Fluid any higher than that would come out and you'll know your system is overfull.