The junction of the exhaust manifold with the mating plane of the cylinder head is sealed with a metal gasket. If the gasket has burned out or the manifold mounting nuts have become loose, exhaust gases can escape through this connection, which is accompanied by a characteristic sound. If tightening the exhaust manifold mounting nuts does not eliminate the defect, it is necessary to replace the gasket.
To avoid burns, it is recommended to start work after the exhaust system has cooled down.
Disconnect the oxygen concentration sensor wiring harness from the engine management system wiring harness (see Removal the oxygen concentration control sensor).
We unscrew the nuts of the studs securing the flanges of the catalytic converter and the exhaust manifold (see Removal the catalytic converter).
We take out the oil dipstick and insert a paper plug into its tube.
We moisten the nuts securing the exhaust manifold to the cylinder head with penetrating liquid.
Using a 12 mm socket, unscrew the ten nuts securing the exhaust manifold to the cylinder head.
If the nuts are stuck to the studs, they may come off along with the studs. This is normal.
We move the exhaust manifold along the remaining studs of the cylinder head and remove it upwards.
We remove the metal gasket of the exhaust manifold.
We unscrew the remaining nuts on the studs.
We apply a thin layer of thread sealant to the threaded part of the stud that is screwed into the cylinder head.
Before screwing the stud into the cylinder head, screw two nuts onto its threaded part and tighten them together. In this form, screw the stud until it stops and, having unfastened the nuts, unscrew them.
Further assembly is carried out in reverse order.
Before installing the exhaust manifold, clean the mating surfaces of the cylinder head and exhaust manifold from carbon deposits and install a new gasket.
Before tightening the new exhaust manifold mounting nuts, apply graphite grease to the cylinder head studs.
Tighten the exhaust manifold mounting nuts to the specified torque.
Tightening order of exhaust manifold mounting nuts