Exhaust system, checking for leaks

Start engine and run at idling speed.
Plug the tailpipes (e. g. with rags or stoppers) and leave plugged until the check is complete.
Listen for noise at the connection points (cylinder head/exhaust manifold, exhaust manifold/turbocharger, turbocharger/front exhaust pipe etc.) to determine whether there are any leaks.
Repair any leaks that are found.