Exhaust system - general information and component renewal

Fuel and exhaust systems / Exhaust system - general information and component renewal

Warning: Inspection and repair of exhaust system components should be done only after enough time has elapsed after driving the vehicle to allow the system components to cool completely. This applies particularly to the catalytic converter, which runs at very high temperatures. Also, when working under the vehicle, make sure it is securely supported on axle stands.

1 The exhaust system is composed of an exhaust manifold, the front downpipe and catalytic converter, and a rear section incorporating two silencers (three on some versions) and the tailpipe assembly. The service replacement exhaust system consists of three or four sections: the front downpipe/catalytic converter, the intermediate pipe and front silencer, and the tailpipe and rear silencer. On some versions, the tailpipe is in two pieces, with two rear silencers. The system is suspended throughout its entire length by rubber mountings.

2 If any of these parts are damaged or deteriorated, excessive noise and vibration will occur.

3 Conduct regular inspections of the exhaust system, to keep it safe and quiet. Look for any damaged or bent parts, open seams, holes, loose connections, excessive corrosion, or other defects which could allow exhaust fumes to enter the vehicle. Deteriorated exhaust system components should not be repaired - they should be replaced with new parts.

4 If the exhaust system components are extremely corroded or rusted together, they will probably have to be cut from the exhaust system. The most convenient way of accomplishing this is to have a quick-fit exhaust repair specialist remove the corroded sections. If, however, you want to save money by doing it yourself (and you don’t have an oxy/acetylene welding outfit with a cutting torch), simply cut off the old components with a hacksaw. If you have compressed air, special pneumatic cutting chisels can also be used. If you do decide to tackle the job at home, be sure to wear eye protection, to protect your eyes from metal chips, and work gloves, to protect your hands. If the production-fit system is still fitted, it must be cut at the points shown (see illustrations) for the service-replacement system sections to fit.

17.4A Cutting point for renewal of production-fit exhaust system - 1.6 and 1.8 models

17.4B Cutting points for renewal of production-fit exhaust system - 2.0 models

5 Here are some simple guidelines to apply when repairing the exhaust system: Warning: The catalytic converter operates at very high
temperatures, and takes a long time to cool. Wait until it’s completely cool before attempting to remove the converter. Failure to do so could result in serious burns.

(a) Work from the back to the front when removing exhaust system components.

(b) Apply penetrating fluid to the exhaust system component fasteners, to make them easier to remove.

(c) Use new gaskets, rubber mountings and clamps when installing exhaust system components.

(d) Apply anti-seize compound to the threads of all exhaust system fasteners during reassembly.

(e) Note that the downpipe is secured to the manifold by two bolts, with a coil spring, spring seat and self-locking nut on each.

On refitting, tighten the nuts until they stop on the bolt shoulders; the pressure of the springs will then suffice to make a leakproof joint (see illustration).

17.5 Tighten exhaust system front downpipe-to-manifold nuts as described - do not overtighten them

Do not overtighten the nuts to cure a leak - the bolts will shear. Renew the gasket and the springs if a leak is found (also see Chapter 2, Part A).

(f) Be sure to allow sufficient clearance between newly-installed parts and all points on the underbody, to avoid overheating the floorpan, and possibly damaging the interior carpet and insulation. Pay particularly close attention to the catalytic converter and its heat shield.