NHTSA Complaint #11657826 — 2021 CHEVROLET SUBURBAN

While driving cross-country, my 2021 Chevrolet Suburban Z71 (5.3L V8) experienced several progressive symptoms leading to total engine failure. For months prior, there was a noticeable coolant smell from the engine bay despite no visible leaks. Multiple Chevy/GM shops noted the smell, and pressure tests showed no external coolant loss. On the trip to Colorado, the engine ran normally, but at idle, the temperature would steadily rise to ~235°F before fans would engage. Upon arrival in Colorado, I found the coolant reservoir was low again. The final time the vehicle started, it shook violently at idle for nearly a minute before settling. The next day, it would crank but failed to start, and has not started since. There were no check engine lights or warning messages at the time of failure. A GM dealership has since diagnosed the engine as “locked up” and quoted a $14,500 remanufactured engine replacement (GM Part 19420610). I’ve been told my engine is the 5.3L V8 (RPO L84), which is currently not included in GM’s safety recall 25V-274 affecting similar failures in the 6.2L L87 engines. Right before this occurred, I had a NC inspection (passed), a fresh oil change the same day, and had coolant added. This failure happened without warning, while traveling out of state, leaving the vehicle stranded in a garage and requiring towing. The situation presented a safety risk and significant financial burden. Given the similarities in symptoms and failure type to the recalled L87 engines, I believe this may be a related manufacturing issue.