What was found
PDX FLIGHT NR 2036, STARTED NR 2 ENGINE, TURNED ON NR 2 BLEED, GOT HAZE IN COCKPIT AND CABIN. SMELLED LIKE DIRTY GYM SOCKS. REMOVED, CLEANED AND REINSTALLED NR 2 ENGINE P2.5/P3.0 AIR PRESSURE SWITCHING VALVE. NO DEFECT FOUND. REPLACED DAMAGED O-RINGS ON NL SPEED SENSOR PROBE AND NL SENSOR PORT SEALING TUBE. GROUND RAN NR 2 ENGINE WITH BLEED ON AT FEATHER FOR 15 MINUTES AND 70 PERCENT TORQUE/1050 RPM FOR 15 MINUTES WITH CABIN. COCKPIT TEMP SELECTIONS BETWEEN HOT AND FULL COLD. NO ABNORMAL ODORS OR VISIBLE HAZE NOTED. AIRCRAFT RETURNED TO SERVICE.