where is the cylinder head temperature sensor located on the engine?

Hello, why are you looking for the sensor -- perhaps you should check the temperature? Maybe it's too hot? You also didn't indicate the engine your MKZ is equipped with, so I'll assume 4 cylinder, 2.0L. The sensor is attached to the cylinder head, requiring access to the air cleaner pipe and turbocharger inlet pipe. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops