The additional muffler is also different - its front pipe is shorter and is equipped with a flange for attaching the converter. Mufflers and neutralizer are non-separable units and should be replaced with new ones in case of failure.
The exhaust manifold is cast iron. A metal-reinforced heat-resistant gasket is installed between it and the cylinder head. A receiving pipe is attached to the manifold on four studs. The connection is sealed with a heat-resistant gasket. Fastening nuts - brass or copper-plated and secured against loosening by locking plates (one for two nuts), the edges of which are bent on the verge of nuts. The downpipe is additionally attached with a clamp to the bracket on the gearbox.
On cars with carburetor engines, the muffler pipes are pushed into each other and fixed with clamps. On vehicles equipped with an injection system, the connections of the converter with an additional silencer and exhaust pipe are flanged, the front one is with a ball joint (pipes can be rotated relative to each other at a small angle without loss of tightness), its mounting bolts are spring loaded.
The converter is used to reduce emissions of carbon monoxide and nitrogen oxides into the atmosphere. It consists of two ceramic blocks with many pores, coated with so-called afterburning catalysts: rhodium, palladium, platinum. Passing through the pores of the neutralizer, toxic carbon monoxide (SO) turns into low-toxic dioxide (CO2), and nitrogen oxides are reduced to harmless nitrogen. The degree of gas purification in a serviceable converter reaches 90–95%. For normal operation of the converter, the composition of the exhaust gases (in particular, their oxygen content) must be within strict limits. This function is performed by the controller, changing the amount of fuel supplied depending on the readings of the oxygen sensor (see Injection engine control system). The converter and oxygen sensor are very sensitive to lead compounds - «poisoned» them, they stop working. Therefore, if the car is equipped with a converter, its operation is strictly prohibited (even short-term) on leaded gasoline. Another reason for the failure of the converter is interruptions in the ignition system: unburned fuel burns out in the converter, damaging the ceramics. This can lead to blockage of the exhaust system and stop the engine (or severe loss of power).
The main muffler is located in a niche in the rear of the body. It is attached to the body brackets on two rubber pads. The middle part of the exhaust system (with additional silencer) does not have attachment points to the body. To protect the floor of the body from excessive heating, a protective screen is fixed above the main muffler.
Maintenance of the exhaust system consists of periodically inspecting pipes and mufflers for corrosion and tightening or replacing loose connections.