Catalytic Converter: Service and Repair
CATALYTIC CONVERTERREMOVAL
WARNING: THE NORMAL OPERATING TEMPERATURE OF THE EXHAUST SYSTEM IS VERY HIGH. THEREFORE, NEVER ATTEMPT TO SERVICE ANY PART OF THE EXHAUST SYSTEM UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE TAKEN WHEN WORKING NEAR THE CATALYTIC CONVERTER. THE TEMPERATURE OF THE CONVERTER RISES TO A HIGH LEVEL AFTER A SHORT PERIOD OF ENGINE OPERATION TIME.
1. Remove muffler and exhaust pipe.
2. Disconnect the downstream oxygen sensor electrical connector.
3. Remove the exhaust manifold support bracket (LEV only) (Fig. 7).
4. Remove catalytic converter to exhaust manifold attaching fasteners and remove converter from vehicle (Fig. 8).
5. Remove and discard the flange gasket.
NOTE: When replacement is required on any component of the exhaust system, original equipment parts (or equivalent) must be used.
INSPECTION
WARNING: THE NORMAL OPERATING TEMPERATURE OF THE EXHAUST SYSTEM IS VERY HIGH. THEREFORE, NEVER ATTEMPT TO SERVICE ANY PART OF THE EXHAUST SYSTEM UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE TAKEN WHEN WORKING NEAR THE CATALYTIC CONVERTER. THE TEMPERATURE OF THE CONVERTER RISES TO A HIGH LEVEL AFTER A SHORT PERIOD OF ENGINE OPERATION TIME.
Check catalytic converter for a flow restriction. (Refer to - EXHAUST SYSTEM - DIAGNOSIS AND TESTING) Exhaust System Restriction Check for procedure.
Visually inspect the catalytic converter element by using a borescope or equivalent. Remove oxygen sensor(s) and insert borescope. If borescope is not available, remove converter and inspect element using a flashlight. Inspect element for cracked or melted substrate.
NOTE: Before replacing a catalytic converter, determine the root cause of failure. Most catalytic converter failures are caused by air, fuel or ignition problems. (Refer to Appropriate Diagnostic Information) for test procedures.
INSTALLATION
NOTE: When assembling exhaust system do not tighten clamps until all components are aligned and clearances are checked.
1. Assemble catalytic converter to exhaust manifold connection. Use a new flange gasket.
2. Install exhaust manifold support bracket (LEV only). Tighten M10 bolt to 54 Nm (40 ft. lbs.), M12 bolt to 95 Nm (70 ft. lbs.), and nut to 28 Nm (250 inch lbs.).
3. Install bolt attaching manifold support bracket to the heat shield (NLEV only). Tighten bolt to 28 Nm (250 inch lbs.).
4. Assemble muffler and exhaust pipe to catalytic converter. Install muffler and pipe support isolators to the underbody.
5. Tighten the catalytic converter to exhaust manifold fasteners to 28 Nm (250 inch lbs.) (Fig. 8).
6. Working from the front of the system; align each component to maintain position and proper clearance with under body components. Tighten all slip joint band clamps to 47 Nm (35 ft. lbs.).
CAUTION: Exhaust band clamps should never be tightened such that the two sides of the clamps are bottomed out against the center hourglass shaped center block. Once this occurs, the clamp has lost clamping force and must be replaced.
7. If removed, install downstream oxygen sensor.
8. Connect downstream oxygen sensor electrical connector.
9. Start the engine and inspect for exhaust leaks. Repair exhaust leaks as necessary.
10. Check the exhaust system for contact with the body panels. Make the necessary adjustments, if needed.