What was found
WITH APU AND ENGINE BLEED AIR ON A STRONG MUSTY ODOR IS OBVIOUS THROUGHOUT THE COCKPIT AND CABIN. FOUND ODOR COMING FROM ACM WATER SOCK, CLEANED SOCK AND RE-INSTALLED, RAN APU AND ENGINE. RAN COCKPIT AND CABIN TEMP. THROUGH FULL HOT AND COLD NO STRONG ODOR NOTED. IAW MM 21-51-00.