Is it safe to work under a vehicle if it is supported only by a jack?

When working under a vehicle, safety is the top priority, and relying solely on a jack does not provide adequate support. Jacks are designed for lifting and may not be stable enough to prevent a vehicle from falling if there's a failure or an accidental bump. They can lose their hydraulic pressure, or the vehicle can shift, leading to dangerous situations.

Using additional support, such as jack stands, significantly increases safety. Jack stands provide a stable platform that can securely hold the vehicle in position, reducing the risk of the vehicle collapsing while a technician is working underneath. This practice aligns with safety standards and best practices in the automotive industry, where the risk of serious injury from a falling vehicle is well understood.

Therefore, it's essential to always use proper lifting methods and equipment, ensuring a safe working environment beneath the vehicle.