Accessories

Accessories for exhaust pipes and silencers ensure gas-tight connections, controlled mounting and sufficient freedom of movement for thermal expansion. Exhaust clamps, connecting sleeves, sealing rings, silencer straps, mounting brackets and rubber-to-metal mounts all help determine the service life of the complete exhaust system. An incorrectly selected clamp or a worn mounting point can cause recurring leaks, even if the exhaust pipe or silencer has recently been replaced.

Heat shields limit radiant heat from hot exhaust components reaching surrounding parts. They protect wiring harnesses, fuel and brake lines, plastic parts and the cab or vehicle floor from overheating and heat damage. Depending on the variant, they are fitted near the exhaust manifold and turbo connection, along exhaust pipes and around silencers or exhaust aftertreatment components such as catalytic converters and particulate filters. They are secured to the designated points on the exhaust component, engine, chassis or bodywork, positioning the shield between the heat source and the parts requiring protection. Maintain the specified air gap and clearance for thermal expansion; the correct position and mounting arrangement depend on the variant.

Always identify parts using the vehicle's chassis number. Visual comparison or selection based solely on the model name is never sufficient. Connections and mounting points on MAN TGL and TGM with D08 engines differ from those on variants with D26 engines. For Mercedes Atego with OM 936 and Actros with OM 471, the emissions specification, exhaust configuration and production date are also decisive. Buses such as Lion’s City and Citaro and vans such as TGE and Sprinter also use variant-specific mountings.

Distinguish between U-bolt clamps for suitable slip joints, band clamps for pipe joints designed for them and V-band clamps for profiled flanges. These designs are not interchangeable. Check the pipe outside diameter, wall thickness, overlap length, flange profile, clamp width and thread. Measure slip fits against the factory tolerances: excessive clearance causes leaks, while an overly tight fit hinders assembly and expansion.

Material selection depends on temperature, exposure to condensate and the corrosiveness of the environment. Aluminised steel and stainless steel have different properties; sealing rings must be suitable for the specific flange design and temperature zone. For rubber exhaust mounts, elastomer quality, hardness and load capacity are important. Follow the vehicle specifications for gas pressure, temperature resistance and tightening torque rather than using a single universal value.

Black soot marks around joints indicate exhaust gas leaks. Rattling at idle is consistent with loose silencer straps, torn rubber exhaust mounts or contact with the chassis. Recurring fractures next to a clamp often indicate installation stress, insufficient support or excessive engine movement. Corrosion beneath mounting straps can remain hidden until the silencer wall fails locally.

1. Allow the exhaust system to cool, secure the vehicle and support heavy silencers before releasing any fixings. Inspect clamps, threaded studs, sealing surfaces and mounting points for cracks, rust and signs of movement.
2. Measure pipe diameters in several directions using a vernier calliper to check for ovality. Check accessible flat flange faces with a straightedge and feeler gauge; compare deviations with the manufacturer's limits.
3. Check the mounting system for play and collapsed rubber-to-metal mounts. Also assess the engine mounts and flexible exhaust sections: a new mounting will not resolve excessive powertrain movement.
4. If a leak is suspected, carry out a smoke test on the cooled system using a regulated low test pressure in accordance with the workshop procedure. If there is a loss of power, measure exhaust back pressure at the specified measuring point and under the stated operating conditions; leaks and blockages require different repair measures.

Clean the sealing surfaces without damaging the flange profile. Replace distorted clamps, damaged threaded fasteners and sealing rings specified as single-use. Do not try to seal an oval pipe by applying extra tightening torque: repair or replace the damaged pipe section. Only use exhaust assembly paste if the manufacturer permits it for that joint.

Initially assemble the joints loosely, align the silencer and pipes, and check the clearance to the chassis, lines and heat shields. Support the weight at the intended mounting points, not at the turbo connection. Tighten the fixings with a torque wrench in the specified sequence. Then check for leaks and vibration during warm-up, using suitable exhaust extraction equipment. Check again once the system has cooled; retighten only if required by the fitting instructions.