My H80 dumped coolant on everything after a year in. Ended up having to build a new PC. I had some very nice parts ruined at that time (3570k, GTX570HD, Antec 850 HCP, Wireless card, 16 GB of RAM). Only thing I ended up reusing in the new build were the hard drives. The case would have been fine, but I wanted to replace it anyways.
I came back from vacation turned the PC on, and there was a small leak, I heard a sizzle come from the machine, looked in and saw it on the GPU. Pulled the cover off, and literally touched a hose and dumped coolant everywhere.
I've heard of people getting partially reimbursed for damaged hardware, but I didn't try and go that route.