Some Lincoln MKZ owners report experiencing check engine light issues related to engine cylinder cracks and coolant leaks, particularly in the 2017 model with the 2.0L EcoBoost engine. These problems are often attributed to factory defects in the water jacket design, leading to coolant intrusion into the cylinder, which can result in engine failure, overheating, and even a potential fire risk. Additionally, some owners have noted that a cracked head may cause coolant to leak into the exhaust ports, necessitating engine replacement. Common symptoms include a check engine light indicating a misfire on a specific cylinder, such as Cylinder 2, along with low coolant levels. It is important for owners to pay attention to trouble codes, as they can provide valuable insight into the vehicle's issues. Furthermore, if the check engine light is flashing, it indicates a detected misfire, and it is advised not to drive the vehicle to avoid further damage. Prompt resolution of these issues is essential for the safety and proper functioning of the Lincoln MKZ.

A coolant leak may develop from the heater core. The failure may be due to electrolysis. Our technicians recommend to check for voltage in the coolant with the battery disconnected. If voltage is found the cooling system should be flushed and jumper wires added to engine ground straps as necessary.