What was found
PASSENGERS COMPLAINED OF BOTH EXCESSIVE HEAT & EXHAUST ODOR. AIR FLOWS FROM BOTH COCKPIT & CABIN, WEMACS VERY LOW FROM ENGS ONLY, IMPROVES WITH APU ON LINE. WHEN AN INFLIGHT APU START WAS ATTEMPTED THE EXHAUST GAS ODOR WAS VERY STRONG. COMPLIED WITH APU, LT & RT ENG RUNS. COMPLYING WITH AIR CABIN & COCKPIT COOLING & HEATING, NO DEFECTS NOTED AT THIS TIME. DID NOTE EXHAUST ODOR IN CABIN PRE APU & ENG RUN, BUT NOTHING DURING RUN & OPS CHECK. NO EXCESSIVE HEAT NOTED IN COCKPIT IAW MM 21-60-00.