At idle have exhaust fumes coming thru aircondition system on 2004 Lincoln LS

Was told it was the PVC hosing on top of engine...replaced...after 2 weeks same problem. Was also told the head gasket was NOT leaking. Smells like oil burning!

1 answer
Check for oil leaking onto the exhaust system. Check the valve cover gaskets, as these are right above the exhaust manifolds