TM  55-2840-241-23 a. Prepare two to four quarts of cleaning solution con- sisting of one part cleaning compound (items 39, 40, 41, 42, table 2-2) to four parts of clean water (distilled if available). Do not substitute petroleum base solvent or jet fuels for recommended cleaning com- pound. Damage to compressor plastic lining could result. b. Retain the anti-icing air valve in the closed posi- tion. c. Inspect  P c tube at scroll and filter ends for cracks and fretting wear. Closely check the areas covered by the floating ferrules and the flared ends. Inspect the scroll for cracks at the junction with P c elbow. d.  Disconnect the control air and compressor bleed valve pressure sensing tubes at the diffuser scroll pres- sure probes. Cap both pressure probes and plug all open sensing lines. Block the compressor bleed valve in the closed position using the compressor protector cleaning kit, tool No. 68886204. (See figure 2-4.) Refer to TM 55-1520-228-23  for  airframe  bleed  air  operated  sys- tems. e. Remove the burner drain valve (14, figure 3-8) from the bottom drain port on the outer combustion case. f. Deactivate the ignition system by diconnecting the power lead to the ignition exciter or pull engine ignition circuit  breaker. Do not exceed 10% N1 motoring speed dur- ing the cleaning and rinsing cycles to prevent possible  blade  damage  and  assure  adequate rinse/cleaning at the base of the blades. Do not inject a solid stream of fluid into the com- pressor. Damage to compressor could occur. g. Spray cleaning solution into the compressor inlet using a low pressure type sprayer equipped with a quick opening valve while motoring the engine without igni- tion. Start injection 3 seconds prior to starter engage- to 11 seconds until 2 to 4 quarts (1.9 - 3.8) have been utilized. Maintain motoring speed below 10% for the duration of the injection. Disengage the starter if N1 speed is attained. Repeat the injection cycle as ceces- sary until the compressor is clean. h. Within 15 minutes after injection of the cleaning solution, spray clean water (distilled preferred) into compressor. Use methanol water mixture if ambient temperature is below 4°C (40°F). Start injection 3 se- conds prior to starter engagement and inject steam or water at the rate of one pint to one quart in 5 to 10 se- i. Remove the compressor protector cleaning kit and reconnect the control and compressor bleed valve sens- ing tubes. Tighten the coupling nuts to 80 - 120 in. lb. j. Reconnect the power lead to the ignition exciter or reset the IGN ENG circuit breaker. k. Apply antiseize compound (item 15, table 2-2) to the threads and install burner drain valve (14, figure 3-8) with new preformed packing (13) in the bottom drain port of the outer combustion case. Tighten the drain valve to 120 - 140 in. lb. Apply antiseize compound (itm 15, table 2-2) to the threads on the outer end of the drain  valve.  Secure  clamp  and  bracket  assembly  (15)  to the drain valve with jam nut (16). Tighten the jam nut to 55-80 in. lb. and secure with lockwire (item 32, table 2-2). l. Start and operate the engine for a minimum of five minutes. Operate the engine anti-icing system to purge solution from the compressor front support. Also, oper- ate any aircraft systems which use compressor bleed air. Complete the engine drying run within 15 minutes after cleaning and rinsing. Using the soap solution, mainte- nance operation check (MOC) is required to verify that the reconnected   P c line and bleed valve line do not leak. NOTE An EPC and torsional oscillation check is not required for routine 50 hour engine flushes unless poor engine performance is noted. 7-4. Compressor Rinsing to Remove Salt Water Contamination. Allow the engine to cool for a minimum of 45 minutes  prior  to  spraying  the  compressor. Mandatory cooling period is required to prevent warpage to internal engine compo- nents. The compressor shall be rinsed if operated within 200 miles of volcanic activity or operated within 10 miles of salt water and on all engines operated below 1000 feet (304.8m) over salt water shall overgo cleaning accord- ing to the following procedure after shutdown following the last flight of the day. Use the procedure in paragraph 7-3 with the following additions. 7-2 Change 23 If any cracks in the Pc tube, ferrules, flared ends and elbow P c elbow junction is suspected, refer to TM 1-1520-254-23, Technical Manual Aviation Unit Maintenance (AVUM) and Aviation Intermediate Maintenance (AVIM) Manual Nondestructive Inspec- tion Procedure for OH-58 Helicopter Series. conds. Disengage the starter before N1 speed accelerates above 10 . °