What was found
IN FLIGHT, WITH WING ANTI-ICE ON, A STRONG ODOR IN COCKPIT AND CABIN. NOT VERY EVIDENT WITH ONLY ENGINE STAB ANTI-ICE ON. APU WAS OFF. ALSO EXPERIENCED TO A LESSER DEGREE DURING GROUND CHECK. REMOVED THE LT ENGINE DUE TO CAUSING STRONG ODOR IN COCKPIT AND CABIN & INSTALLED A NEW SERVICEABLE ENGINE. PERFORMED AN OPS CHECK AND LEAK CHECK WITH NO DISCREPANCIES NOTED. ALL WORK PERFORMED IAW AMM 71-00-10, 710-00-30, 71-00-10 AND EMM 71-00-00.