QUOTE(clawhammer @ Sep 24 2009, 01:52 AM)
I normally start the PSU without the motherboard and see if there's any leakage. That's the only thing I do and I've never done any specific leak test but after all these years, I'm still doing fine

You just have to make sure all the barbs are tighten and your tubings are tightly fitted.
In my case, I'm doing the leak testing with all the required hardware hooked up (mobo, CPU and GPU if you have your GPU in the loop). Obviously, I only powers the pump.
The reason is because although you leak test w/o hardware and have no leak, it may still leak once you put everything together. There is a thread on XS forum where people about people leak's stories, and I think there are at least 2 of them who had leak test w/o hardware but then got a leak once everything was hooked up.
It is because w/o hardware the tubing can "hang" where it wants to as it is free. But once hooked up, there may be just a little bit more stress on the tubing because then you have to make the tube go where YOU want to. In the 2 stories, that little more stress on the tubing actually made the barbs unscrews themselves just a little bit then provoking a little leak.
Moreover, even if water goes on the hardware and it's not powered, it is almost impossible that the hardware gets damaged ... except if you leave it soak in the water for 24 hours
If there is water, you just dry thoroughly with warm hair dryer /and/or pure alcohol and leave it dry for 24 hours.
But then clawhammer as much more experience than I have, so I guess you can also do it w/o hardware if you do it the right way

I am just pointing out for new comers so they can be aware of this possible problem. If you leak test w/o hardware, make sure you force the blocks to be as closed as possible as there final position to make sure the extra stress won't make the barb loose
This post has been edited by r4st4m4n: Sep 24 2009, 02:06 PM