Honestly, you mistook me on the long post thing. I didn't want to MAKE a long post by using the whole post you made + mine. Sorry, I worded that wrong. My bad. I want to be very rank with everyone. When I 1st push the power button on my computer, it makes a loud rattling noise similar to what you are hearing, it happens. After the pump gets caught back up it slowly dies down and will disappear over the sound of the fans. Very similar to my common use of a fish tank pump. When you unplug it, and the water in it goes to the lowest point in the system, then plug it back in, it's going to rattle and make noise until it catches back up.
Nextly, do you have THE PUMP hooked up to the motherboard header or the PSU. If connected to the motherboar, go into BIOS, find the Fan settings for that particular fan header, and set them to MANUAL 100% speed, then let it run for a little while. Also set the Power options in windows to Active cool on the CPU Options in Advanced power options.
But the noise you are describing the 'swoosh' that stays for a few seconds or minutes, thats the normal noise of the air and water traveling through the pump. It barely last's 30 seconds and then the pump dies down with no noise at all. Thats no problem..all pumps do that, The noise I am describing comes after the pump dies down, it sounds similar to a electric shaver. "dhuuuuuurrrrrrrr dhik dhik dhurrrrrrrrrrrrr" or like when a older hdd is trying to access data. I tried everything I could, even left it running with the computer on for 12 hours overnight thinking it will auto fix itself, no recovery.
I have tried hooking it up to he motherboard CPU header(which is set to 100% in the BIOS), also have hoked it to the PSU using a molex to 3 pin connector. left it there for hours, with no sign of improvement. Its a bad pump, possibly the impaler shaft. This has happened to me many times. My friends one still works fine(bought from the same retailer)