Got my WC built last night and it was running leak-free for a couple of hours. Decided to turn my MCP-655 down as I was getting major turbulence in my bay res on 5. Because of where I positioned the pump (realistically there was nowhere else for it to go) I have to dismount it and twist it to reach the potentiometer. After turning it down to ~3.5 (for some reason it makes a boatload of noise on 3 so I turned it up until it went quiet again) I just had a nice gentle sloshing in there, but my fingers came away covered in Feser One 
Turned the pump off and felt around - actually seemed like the leak was coming from the pump itself. Toweled it all down (gotta love this coolant - very easy to find where it's gone with a UV CCFL) and decided to put hose-clamps on the pump fittings (never had to before with 7/16" tubing onto 1/2" barbs). It has now run for 14 hours without a leak, but I'm still kinda worried (if the pump leaks it will drip coolant straight onto a 1650rpm Yate Loon which will no doubt fling it everywhere if it is running at full speed). A friend of mine did accidentally unscrew the impeller assembly a bit while it was sitting around (I didn't even know you could), but I made sure it was nice and tight again before using it. Am I getting worked up over nothing, or has a seal been broken somewhere (haven't had the pump apart, so don't know what the innards look like).
Turned the pump off and felt around - actually seemed like the leak was coming from the pump itself. Toweled it all down (gotta love this coolant - very easy to find where it's gone with a UV CCFL) and decided to put hose-clamps on the pump fittings (never had to before with 7/16" tubing onto 1/2" barbs). It has now run for 14 hours without a leak, but I'm still kinda worried (if the pump leaks it will drip coolant straight onto a 1650rpm Yate Loon which will no doubt fling it everywhere if it is running at full speed). A friend of mine did accidentally unscrew the impeller assembly a bit while it was sitting around (I didn't even know you could), but I made sure it was nice and tight again before using it. Am I getting worked up over nothing, or has a seal been broken somewhere (haven't had the pump apart, so don't know what the innards look like).