would reccomend taking off that line and taking to an auto parts store. Basically diameter is usually 3/16 or 1/4, but there are many different threads and fittings. So, best to take with so can match up all aspects.
3/16 on my 02 rio if that helps any. Also if the connectors aren't the same get yourself a double flare tool so you can reuse the original connectors if you need to, and a bending tool helps also. Reguards Ronjohn good luck