@clunk

thanks for your participation...did you measure(perhaps an infrared temp meter) the radiator body temp? measuring such would indicate water/fluid temp.... based on some radiator testing.and i860 heat output ...i'm guessing the water temps are as high as 10-20c above room temperatures...such high water temps could cause the the failure of your oc tests...i mean instead of a cold plate..you have a warm plate and the cpu would just heat up eventually...