I don't think so, the overflow hose is also collapsing but that does give me an idea. Maybe the cheap overflow tank is plugged. It is coming off the car tonight for inspection. It was only $8 & you get what you pay for. I just added it for now to keep antifreeze from spilling out. My plan was to get a nicer one once I get the car painted & drop a new motor in it; this one was just to do the job with little expense involved. Could a plugged little overflow line cause that much vacuum to build up? It is the flimsiest hose I have seen. Now I can't wait to get home & test the theory. Thanks daredevil.
