Cadillac CT4 2019–2024 — technical service bulletin
Bulletin 21-NA-240 · NHTSA communication 11019543 · issued Apr 22, 2025
Technical service bulletin
communication type
Engine
component
2019–2024
model years
37
vehicle entries
Official summary
This service bulletin provides diagnostic repair information to correct an oil leak in the engine.
Vehicles covered
- 2020 Cadillac CT4
- 2021 Cadillac CT4
- 2022 Cadillac CT4
- 2023 Cadillac CT4
- 2024 Cadillac CT4
- 2020 Cadillac CT5
- 2021 Cadillac CT5
- 2022 Cadillac CT5
- 2023 Cadillac CT5
- 2024 Cadillac CT5
- 2019 Cadillac CT6
- 2019 Cadillac XT4
- 2020 Cadillac XT4
- 2021 Cadillac XT4
- 2022 Cadillac XT4
- 2023 Cadillac XT4
- 2024 Cadillac XT4
- 2019 Cadillac XT5
- 2020 Cadillac XT5
- 2021 Cadillac XT5
- 2022 Cadillac XT5
- 2023 Cadillac XT5
- 2024 Cadillac XT5
- 2020 Cadillac XT6
- 2021 Cadillac XT6
- 2022 Cadillac XT6
- 2023 Cadillac XT6
- 2024 Cadillac XT6
- 2020 Chevrolet Blazer
- 2021 Chevrolet Blazer
- 2022 Chevrolet Blazer
- 2023 Chevrolet Blazer
- 2024 Chevrolet Blazer
- 2020 GMC Acadia
- 2021 GMC Acadia
- 2022 GMC Acadia
- 2023 GMC Acadia
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.