A catch can is a device that is used to collect fluids as they are released from an engine. The catch can is typically mounted on the firewall or fender and has a series of small holes drilled into it that allow the fluid to be collected and then drained away.
While a catch can will not cause any problems if installed correctly, there are a few things that can go wrong. If the catch can is not vented properly, pressure can build up inside of it and cause the engine to run leaner than normal. This can lead to engine damage over time. Additionally, if the catch can is not installed in the correct location, it may not be able to properly collect all of the fluid being released from the engine, which could lead to leaks.