What was found
ON CLIMBOUT, DUCT SPLIT 20 PSI FOR DIFFERANCE AND 18 PSI MIN. RT SIDE IS LOW LT SIDE NORMAL. CRUISE GIVES NORMAL INDICATIONS. LT SIDE DURING CLIMB 38, RT SIDE 18. CRUISE, RT SIDE 38, LT SIDE 36. N1 AT 88.9, RT WAS 30, LT WAS 36. SUBSEQUENT FLIGHTS RT BLEED LIGHT CAME ON. ACFT GROUNDED. PERFORMED FIM TASK 36-10-00-810-809, FOUND PRECOOLER CONTROL VALVE BAD. R & R PRECOOLER CONTROL VALVE IAW AMM 36-12-02. OPS / LEAK CHECK GOOD.