We demonstrate highly quick response and long distance distributed oil sensors using a newly developed eccentric core fiber (ECF). This distributed oil sensor,based on an interaction between measurand oil and evanescent-wave from the ECF, has achieved as short as 4 minutes response time by using an improved coating material and a sensing length over 17 km at a signal wavelength of 1310 nm. The observed sensitivity characteristics coincide with the calculations of the evanescent power outside the cladding and it is shown that the sensitivity can be well estimated from the amount of the outer cladding component of the evanescent power.