Well, I almost did. I did this when I was a complete noob to watercooling, so please don't flame me . Basically, when I got my MCW5000A, I just screwed the barbs in without silicone gasket sealer. I leak tested for 48 hours and the system actually ran for about 8 days before one of the barbs sprang a leak and almost killed my 9800 Pro. Thank god I put that northbridge fan there, otherwise I'd be short $250.