Cooling fan noise, broken radiator strap
One of the two straps that go around the radiator snapped off at the bottom and was slapping the core when the fan went to high speed. I was able to get the broken piece out before it did any damage. I only see these straps on stock radiators, and it seems they aren't replaced when you get it re-cored? It looks like they hold the top and bottom together, but everything is still tight without it. Will something fall apart with one of them missing? It's the ones that look like packaging material.