What size impact wrench do I need?
Short answer: A 3/8 inch compact impact handles most engine bay and interior fasteners, a 1/2 inch mid or sub-compact covers lug nuts and suspension, and a high-torque 1/2 inch handles stubborn large fasteners.
Impact wrenches come in different drive sizes and power levels. Compact 3/8 inch tools are light and reach tight places. 1/2 inch mid-size and sub-compact tools balance power and size for wheel and suspension work. High-torque tools break loose seized fasteners.
Check the maker's specifications for the tools you are considering, and pick a size suited to your typical work. Many technicians own two sizes.
Use impact-rated sockets, and do not use an impact to final-torque critical fasteners; use a torque wrench. Wear safety glasses and hearing protection.
Tools used for this job
General guidance only. Follow the vehicle and tool manufacturer's procedures, and confirm vehicle coverage on the tool maker's list before buying.