I recently had my cylinder head removed from my 2001 v6 freelander due to a cylinder 6 misfire, during this work two exhaust valves andtwo inlet valves were removed and replaced. The garage also renewed the head gasket and bolts aswell as the timing belt. The cooling system was bled and subsequently refilled. Since this work has been done i have noticed that my engine makes a tapping noise when and during acceleration, there is also a strong burning smell from the exhaust? I took it back to the garage to point out my concerns. They have suggested that the tapping noise is a hole in the exhaust manifold gasket and the strong smell will wear off and is due to the work that has taken place???? in addition the inlet manifold was replaced 6 months ago. ANY SUGGESTIONS