Catalytic Converter and Turbocharger Issues in the 2015 Buick LaCrosse 2.0T

The 2015 Buick LaCrosse 2.0T, particularly in the Chinese market, is equipped with the LTG 2.0T turbocharged engine. This powerplant is also found in other global GM vehicles from similar years, such as certain Cadillac ATS and Chevrolet Malibu models, indicating shared engineering.
A notable issue reported with this engine in the Chinese market LaCrosse is a damaging interaction between the catalytic converter and the turbocharger. If the catalytic converter becomes severely clogged, it creates excessive exhaust backpressure. This increased pressure puts immense strain on the turbocharger.
Prolonged exposure to this high backpressure can cause the turbocharger’s turbine housing, especially near the catalytic converter, to crack due to heat and stress. Cracking not only causes exhaust leaks but can also damage the turbo’s internal seals, leading to oil leaks. This oil leakage can further harm the turbo and potentially foul the already-clogged catalytic converter.
While direct reports of this specific failure sequence (clogged cat leading to cracked turbo housing and oil leak) might not be as prevalent for international models using the same LTG 2.0T engine, the shared components mean the potential for similar issues exists.
For owners of these vehicles, especially the 2015 Buick LaCrosse 2.0T, it is crucial to address symptoms like reduced power or unusual exhaust smells promptly. Checking the catalytic converter for blockage and the turbocharger for leaks or noises can prevent this cascading failure and costly repairs.