The contact owns a 2021 Cadillac XT5. The contact stated that while an oil change was being completed, an oil leak was discovered. No warning light was illuminated. The dealer diagnosed the vehicle and determined that the head gasket needed to be replaced. The vehicle was repaired; however, the failure recurred. The vehicle was taken back to the dealer, where it was diagnosed and determined that the head gasket needed to be replaced. The vehicle was repaired; however, the failure persisted. The vehicle was taken back to the dealer, where it was diagnosed with an internal leak in the engine. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 30,000.

Source: NHTSA complaint ODI #11743461 · view all complaints for this vehicle at nhtsa.gov

The Side Detection System warning light came on. I found that other vehicles in our blind spots were not be recognized by the system. The warning lights were not being activated on the side mirrors. The system was repaired at the dealership at a cost of $865.43. When speaking withe the service technician he said this is happening quite frequently. They found three wires that were corroded and two more that showed signs future issues.

Source: NHTSA complaint ODI #11760426 · view all complaints for this vehicle at nhtsa.gov

When braking — both at low speeds and when slowing from highway speeds (40+ mph) — vehicle feels like engine revs and is still pushing against the brakes. Requires very firm pedal pressure to hold car in place; if brake pressure is eased, vehicle surges forward until it finally settles after several seconds. Concern is intermittent but repeatable. I had a near collision on 10/3/2025 due to this issue. I have been in constant contact with the dealership on this, including the service manager, as well as Cadillac Care. The dealership has test driven the vehicle several times and has been unable to replicate the problem. However, I do have an audio recording of the engine’s idle speed at various points during one incident.

Source: NHTSA complaint ODI #11691365 · view all complaints for this vehicle at nhtsa.gov

I took my SUV to Heritage Cadillac in Lombard, IL for a revving sound while accelerating, specifically from 0-35mph and then acceleration on the highway at higher speeds. It sounded like I was revving the engine even when I wasn't accelerating and stay at a constant speed. There were not any service lights or notification of any issues in my vehicle. The car is at 59,000 miles, I paid $230 for a diagnostic run only to be told it was a "Faulty Muffler" and needed replacement for $1479.66 as it was not covered in my extended warranty. When I took it for a competing bid at a national-brand muffler shop, I was told parts were very hard to get for it as the car was "so new" and that he had another customer bring in for the same problem, but he couldn't find the muffler in his national data base. This lead me to research further why this would happen to a car only 5 year in. This led me down a rabbit hole researching this issue on other Cadillac forums. I'm seeing a recurring pattern among 2020-2021 XT5 owners with the 3.6L engine: a whiny noise when accelerating at low speeds, peaking around 3,000 RPM, traced to loose baffles inside the muffler or a restriction in the exhaust system. Several owners report first noticing it as early as 2,000 miles, with it getting louder over time - which lines up closely with what I experienced. More notably, multiple owners with this exact symptom got their full exhaust systems replaced under warranty, including vehicles with comparable or higher mileage than mine. I've also confirmed there are no open NHTSA recalls on my vehicle, so I know this isn't a recall issue. But given how consistently this specific failure shows up across other XT5s of the same model year and engine, it looks less like isolated wear and more like a known defect pattern.

Source: NHTSA complaint ODI #11748010 · view all complaints for this vehicle at nhtsa.gov