2012 Toyota Prius Owners Manual - Page 1236

4-3. Do-it-yourself maintenance Coolant The coolant level is satisfactory if it is between the full ("FULL" or "F") and low ("LOW" or "L") lines on the reservoir when the hybrid system is cold. Engine coolant reservoir Reservoir cap "FULL" line "LOW" line If the level is on or below the "LOW" line, add coolant up to the "FULL" line. (→P. 501) Power control unit coolant reservoir Reservoir cap "F" line Maintenance and care 4 "L" line If the level is on or below the "L" line, add coolant up to the "F" line. (→P. 501) 377 PRIUS v_U (OM47784U)