Used Car Buying - Body & Frame

Inspecting the body and frame of a used car

Unibody is a popular design for newer cars in which the frame and body are permanently attached and are considered as one component. This means that any extensive rust, or the presence of rot on the frame of the car will require professional repair or replacement at great cost.





Previously when a car had rust on the frame or body you could simply add new metal over the rotted metal with rivets. Since the frame, and thereby body on unibody design cars, is considered part of the crash protection of the vehicle you can no longer simply patch these areas. When a section of floor, frame or subframe needs replacement due to rot strict safety standards must be adhered to. This generally will require professional repair which are labour intensive and costly.


Our expert mechanic tells us that a used car with anything more serious than surface rust on the frame should be avoided altogether.

Locations to check for rust when inspecting a used car

In cold and wet climates especially, the floor on the drivers side must be inspected for holes and rot that would need to be repaired before being able to drive the car. The accumulation of moisture and salt deposits from the drivers feet can cause this area of the car to rust faster than most other areas.





Though many other areas of the car may also rust in an accelerated fashion, such as the wheel wells on the body, the floor of the car is more important from a safety perspective. Holes in the body from rust that do not penetrate into the interior of the car are considered more cosmetic than anything else. Any holes that do penetrate into the interior cab of the car will require repairs in order to pass a safety certification.


For a final look at some items to avoid when buying a used car proceed to the tutorial section on what to avoid when buying a used car.