What are the reasons why a Buick mechanical key cannot unlock the car door?

[VanAna]

If the mechanical key cannot unlock the car door, it is highly likely that there is an issue with the car door lock cylinder, such as rust. Below are precautions for storing car keys: 1. Remove the key promptly: If you need to leave the car, even for just a few minutes, do not leave the key in the ignition. Always turn off the engine, lock the car, take the key with you, and close all windows and the sunroof tightly to prevent giving thieves an opportunity. 2. Do not keep the spare key in the car: Avoid placing the spare key inside the car. Modern car anti-theft systems are generally designed to protect the engine. Even if a thief manages to duplicate a key to open the door, they cannot start the engine and drive away. However, the spare key can start the engine, so it must never be left inside the car, nor should it be used as a regular key for long-term use. 3. Understand insurance coverage: When purchasing car insurance, make sure to understand the details of theft-related compensation to avoid lacking evidence for a claim in case the key is lost and the car is stolen.