It's for the oil cooler mod, witch is weird I know stock k20a2s in stock 02-04 come with the setup already. That's what it looks like. Google up rsx oil cooler.
A forum community dedicated to Acura RSX, ILX and Honda EP3 owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, K24 swaps, turbo kits, and more!