Mazda CX-9 engine failure due to coolant leak, known issue beyond warranty period on Mazda CX-9

Some Mazda CX-9 owners report experiencing engine failures due to coolant leaks, often attributed to common causes such as loose hose connections, broken radiators, failed water pumps, or cracked cylinder heads. Initially, a failing head gasket may not show symptoms until it impacts critical engine components, leading to issues like low coolant levels or dashboard warnings. Notably, some second-generation Mazda CX-9 models have been reported to develop coolant leaks, with documented cases up to the 2020 model year. Signs of a cracked cylinder head can include visible coolant leaks, green residue in the engine compartment, or a flashing thermostat light. Mazda has acknowledged this issue with Technical Service Bulletin TSB 01-002/23, which confirms the coolant leak problem in certain models. Owners facing engine failures due to these leaks beyond the warranty period may face challenges, but some have successfully had their engines replaced even after warranty expiration, suggesting that solutions might still be accessible.