ParkAvenue 1997-1999

Exhaust System

Print

Catalytic Converter



Description & Operation

Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

The catalytic converter is mounted in the engine exhaust stream ahead of the muffler. Its function is to combine carbon monoxide (CO) and hydrocarbons (HC) with oxygen and break down nitrogen oxide (NOx) compounds. These gasses are converted to mostly CO 2 and water. It heats to operating temperature within about 1-2 minutes, depending on ambient and driving conditions and will operate at temperatures up to about 1500°F (816°C). Inside the converter housing is a single or dual bed ceramic monolith, coated with various combinations of platinum, palladium and rhodium.

The catalytic converter is not serviceable. If tests and visual inspection show the converter to be damaged, it must be replaced. There are 2 types of failures: melting or fracturing. The most common failure is melting, resulting from unburned gasoline contacting the monolith, such as when a cylinder does not fire. Usually when the monolith melts, high backpressure results. When it cracks, it begins to break up into small particles that get blown out the tail pipe.

Poor fuel mileage and/or a lack of power can often be traced to a melted or plugged catalytic converter. The damage may be the result of engine malfunction or the use of leaded gasoline in the vehicle. Proper diagnosis for a restricted exhaust system is essential before any components are replaced. The following procedure that can be used to determine if the exhaust system is restricted.

Specific to:

Buick Century 1995-2005

Buick LaCrosse 2005-2007

Buick LeSabre 1990-2005

Buick Lucerne 2006-2007

Buick Park Avenue 1991-2005

Buick Rainier 2004-2007

Buick Regal 1990-2004

Buick Rendezvous 2002-2007

Buick Riviera 1990-1993, 1995-1999

Buick Roadmaster 1991-1996

Buick Skylark 1990-1998

Buick Terraza 2005-2007

Cadillac Allante 1987-1993

Cadillac Catera 1997-2001

Cadillac CTS 2003-2007

Cadillac DeVille 1990-2005

Cadillac DTS 2006-2007

Cadillac Eldorado 1990-2002

Cadillac Escalade 1999-2000, 2002-2007

Cadillac Fleetwood 1990-1996

Cadillac Seville 1985-2004

Cadillac SRX 2004-2007

Cadillac STS 2005-2007

Cadillac XLR 2004-2007

Chevrolet Astro 1985-2005

Chevrolet Avalanche 2007

Chevrolet Avalanche 1500 2002-2006

Chevrolet Avalanche 2500 2002-2006

Chevrolet Aveo 2004-2007

Chevrolet Aveo5 2007

Chevrolet Bel Air 1975, 1981

Chevrolet Beretta 1987-1996

Chevrolet Blazer 1987-2005

Chevrolet C10 1975-1986

Chevrolet C10 Suburban 1975-1986

Chevrolet C1500 1988-1999

Chevrolet C1500 Suburban 1992-1999

Chevrolet C20 1975-1986

Chevrolet C20 Suburban 1975-1986

Chevrolet C2500 1988-2000

Chevrolet C2500 Suburban 1992-1999

Chevrolet C30 1975-1986

Chevrolet C3500 1988-2002

Chevrolet Camaro 1975-2002

Chevrolet Caprice 1975-1996

Chevrolet Cavalier 1982-2005

Chevrolet Celebrity 1982-1990

Chevrolet Chevette 1976-1987

Chevrolet Citation 1980-1983

Chevrolet Citation II 1984-1985

Chevrolet Classic 2004-2005

Chevrolet Cobalt 2005-2007

Chevrolet Colorado 2004-2007

Chevrolet Corsica 1987-1996

Chevrolet Corvette 1975-1982, 1984-2007

Chevrolet El Camino 1975-1987

Chevrolet Equinox 2005-2007

Chevrolet Express 1500 1996-2007

Chevrolet Express 2500 1996-2007

Chevrolet Express 3500 1996-2007

Chevrolet G10 1975-1995

Chevrolet G20 1975-1995

Chevrolet G30 1975-1996

Chevrolet HHR 2006-2007

Chevrolet Impala 1975-1985, 1994-1996, 2000-2001

GMC Caballero 1978-1987

The catalytic converter is a muffler-like container built into the exhaust system. The catalyst element consists of individual pellets or a honeycomb monolithic substrate coated with a noble metal such as platinum, palladium, rhodium or a combination. When the exhaust gases come into contact with the catalyst, it changes residual HC, CO and NOx in the exhaust gas into CO 2 , H 2 O and N, before the exhaust gas is discharged into the atmosphere.

Inspection

Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

  1. Raise and safely support the vehicle.
  2.  
  3. Inspect the catalytic converter protector for any damage.
  4.  

If any part of the protector is dented to the extent that is contacts the converter, replace it.

  1. Check the heat insulator for adequate clearance between the converter and the heat insulator. Repair or replace any damaged components.
  2.  

Flange Type



Removal & Installation

CAUTION
Do NOT perform exhaust repairs or inspection with the engine or exhaust hot. Allow the system to cool completely before attempting any work. Exhaust systems are noted for sharp edges, flaking metal and rusted bolts. Gloves and eye protection are required. A healthy supply of penetrating oil and rags is highly recommended. Never spray liquid rust dissolving agent onto a hot exhaust component.



Click image to see an enlarged view

Fig. Example of a flange type exhaust system joint

Before removing any component on a flange type system, ALWAYS squirt a liquid rust dissolving agent onto the fasteners for ease of removal. Start by unbolting the exhaust piece at both ends (if required). When unbolting the headpipe from the manifold, make sure that the bolts are free before trying to remove them. if you snap a stud in the exhaust manifold, the stud will have to be removed with a bolt extractor, which often means removal of the manifold itself. Next, disconnect the component from the mounting; slight twisting and turning may be required to remove the component completely from the vehicle. You may need to tap on the component with a rubber mallet to loosen the component. If all else fails, use a hacksaw to separate the parts. An oxy-acetylene cutting torch may be faster but the sparks are DANGEROUS near the fuel tank, and at the very least, accidents could happen, resulting in damage to the under-car parts, not to mention yourself.

Inspection



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

Safety glasses should be worn at all times when working on or near the exhaust system. Older exhaust systems will almost always be covered with loose rust particles which will shower you when disturbed. These particles are more than a nuisance and could injure your eye.


CAUTION
DO NOT perform exhaust repairs or inspection with the engine or exhaust hot. Allow the system to cool completely before attempting any work. Exhaust systems are noted for sharp edges, flaking metal and rusted bolts. Gloves and eye protection are required. A healthy supply of penetrating oil and rags is highly recommended.



Click image to see an enlarged view

Fig. Cracks in the muffler are a guaranteed leak



Click image to see an enlarged view

Fig. Check the muffler for rotted spot welds and seams

Your vehicle must be raised and supported safely to inspect the exhaust system properly. Placing 4 safety stands under the vehicle for support should provide enough room for you to slide under the vehicle and inspect the system completely. Start the inspection at the exhaust manifold or turbocharger pipe where the header pipe is attached and work your way to the back of the vehicle. On dual exhaust systems, remember to inspect both sides of the vehicle. Check the complete exhaust system for open seams, holes loose connections, or other deterioration which could permit exhaust fumes to seep into the passenger compartment. Inspect all mounting brackets and hangers for deterioration, some models may have rubber O-rings that can be overstretched and non-supportive. These components will need to be replaced if found. It has always been a practice to use a pointed tool to poke up into the exhaust system where the deterioration spots are to see whether or not they crumble. Some models may have heat shield covering certain parts of the exhaust system , it will be necessary to remove these shields to have the exhaust visible for inspection also.



Click image to see an enlarged view

Fig. Make sure the exhaust components are not contacting the body or suspension



Click image to see an enlarged view

Fig. Check for overstretched or torn exhaust hangers



Click image to see an enlarged view

Fig. Example of a badly deteriorated exhaust pipe



Click image to see an enlarged view

Fig. Inspect flanges for gaskets that have deteriorated and need replacement



Click image to see an enlarged view

Fig. Some systems, like this one, use large O-rings (donuts) in between the flanges



Click image to see an enlarged view

Fig. Exhaust system configuration - 3.8L (VIN 3) engine



Click image to see an enlarged view

Fig. Exploded view of the exhaust system components - 3.8L (VIN L and 1) engines



Click image to see an enlarged view

Fig. Components of the exhaust system - 1997 3.8L (VIN K and 1) engines shown

Removal & Installation



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

There are basically two types of exhaust systems. One is the flange type where the component ends are attached with bolts and a gasket in-between. The other exhaust system is the slip joint type. These components slip into one another using clamps to retain them together.


CAUTION
Allow the exhaust system to cool sufficiently before spraying a solvent exhaust fasteners. Some solvents are highly flammable and could ignite when sprayed on hot exhaust components.

Before removing any component of the exhaust system, ALWAYS squirt a liquid rust dissolving agent onto the fasteners for ease of removal. A lot of knuckle skin will be saved by following this rule. It may even be wise to spray the fasteners and allow them to sit overnight.



Click image to see an enlarged view

Fig. Nuts and bolts will be extremely difficult to remove when deteriorated with rust



Click image to see an enlarged view

Fig. You should always check the exhaust hangers for deterioration



Click image to see an enlarged view

Fig. Exhaust system component replacement

Slip Joint Type



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999



Click image to see an enlarged view

Fig. Example of a common slip joint type system

Before removing any component on the slip joint type exhaust system, ALWAYS squirt a liquid rust dissolving agent onto the fasteners for ease of removal. Start by unbolting the exhaust piece at both ends (if required). When unbolting the headpipe from the manifold, make sure that the bolts are free before trying to remove them. if you snap a stud in the exhaust manifold, the stud will have to be removed with a bolt extractor, which often means removal of the manifold itself. Next, remove the mounting U-bolts from around the exhaust pipe you are extracting from the vehicle. DonO

t be surprised if the U-bolts break while removing the nuts. Loosen the exhaust pipe from any mounting brackets retaining it to the floor pan and separate the components.

 
label.common.footer.alt.autozoneLogo