EMPLOYEE WAS DISMOUNTING CAB OF A CATERPILLAR 777 HAULAGE TRUCK. RADIATOR CAP DISLODGED AND EMPLOYEE WAS ""SPRAYED"" WITH HOT COOLANT RESULTING IN 1ST DEGREE BURNS TO BOTH ARMS AND A SMALL 2ND D EGREE BURN TO TOP OF HEAD. EMPLOYEE JUMPED OFF TRUCK AND FRACTURED RIGHT HEEL (BONE CHIP) AND BRUISED LEFT HEEL.