What causes a liquid cooler to leak?

[ironmetal]

I was thinking of doing liquid cooling in my build but I've seen people say that their liquid coolers leaked. And I was wondering what causes them to leak? I'm new to liquid cooling so I just wanted to know how to avoid a leak. And what causes them.

 

[Gam3r01]

Things that would cause leaks would be a hole in a hose/ hole somewhere, a faulty connector, or a faulty pump. Most liquid coolers have warranties that if they leak they will replace the damage, custom loops have a higher risk of leakage. Most are either misuse or faulty from the start.

 

[manofchalk]

For me its not fully screwing down fittings (typically rotary ones since your have to screw it in multiple places).