GM Conditions

Known GM service conditions can result in damage to the catalytic converter:

Condition: Loss of coolant

Loss of coolant, coolant odor, having to add coolant or a milky substance on either the oil dipstick or oil fill cap. Additionally, owners may indicate that there are signs of coolant loss left on the ground where the vehicle is normally parked

Cause: Condition may be due to coolant leaking past intermediate intake or throttle body gaskets.

Result: Coolant entering the converter causes contamination of the substrate and/or the O2 sensors. Ref: Bulletin No.: 01-06-01-007C

Condition: Loss of power

Vehicles affected: 2001-02 Chevrolet Impala, Monte Carlo, Pontiac Grand Prix, and Buick Regal models equipped with a 3.4L (RPO LA1 – VIN E) or 3.8L (RPO L36 – VIN K) V6 engine.

Cause: May be due to the front endcone insulation from the catalytic converter breaking away and blocking the front of the first catalyst brick.

Result: Prevents the free flow of exhaust gas through the converter. Loss of power, MIL light illumination. Ref: Special Policy Adjustment – Catalytic Converter # 05551

Condition: Poor drivability and/or hard starts

Owner may comment on drivability symptoms or long, hard starts, rough idle and light or intermittent misfire. The Malfunction Indicator Lamp (MIL) may also illuminate.

Vehicles affected:
1994-1996 Buick Regal
1994-1999 Buick Century
1994-1998 Buick Skylark
1994-1996 Chevrolet Corsica, Beretta
1995-1999 Chevrolet Lumina, Monte Carlo
1996 Lumina APV
1997-1999 Chevrolet Malibu, Venture
1994-1996 Oldsmobile Cutlass Ciera
1994-1997 Oldsmobile Achieva, Cutlass Supreme
1996-1999 Oldsmobile Silhouette
1997-1998 Oldsmobile Cutlass
1999 Oldsmobile Alero
1994-1999 Pontiac Grand Am, Grand Prix
1996-1998 Pontiac Trans Sport
1999 Pontiac Montana with 3.1 L or 3.4 L V6 Engine (VINs E, J, M – RPOs LA1, LG8, L82)

Cause: Due to various factors, the fuel injectors may become restricted. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio.

Result: Lean air fuel ratio may either trigger the MIL or cause the engine to develop various drivability symptoms. Higher operating temperatures may burn or even melt the substrate.

Condition: Engine Coolant Leak

Engine coolant may leak at the upper intake manifold throttle body gasket, or at the upper intake manifold to lower intake manifold gasket.

Vehicles affected: All 2000-2002 and certain 2003 Chevrolet Impala and Monte Carlo, Pontiac Grand Prix and Bonneville, and Buick Regal, LeSabre, and Park Avenue models equipped with 3.8L V6 engine (RPO L36 – VIN Code K)

Result: Coolant leak may result in a low engine coolant level and higher engine operating temperatures. Higher temperatures may burn or even melt the substrate. Ref: Subject 03034

Condition: Fuel Leak

Fuel leaks can occur that cause the engine to run rich, extend the crank times, and possibly store DTC codes. When coupled with charging, starter, or battery problems, the condition can lead to the possibility of a fire and/or intake manifold rupture or explosion resulting from a leaky fuel pressure regulator.

Cause:  Fuel leaks can be caused by a leaky or faulty fuel pressure regulator. When the regulator fails, fuel can leak past the rubber diaphragm inside of the regulator housing and raw fuel can then enter the intake manifold.

Result: Raw fuel entering the converter can superheat the substrate causing it to melt. Ref: GM recall 04V090000 and service bulletin 03054B