HKS 4mm Hose Vacuum Cap

This is an HKS 4mm vacuum cap, part number 14999-AK018. It's a straightforward component designed to seal off unused vacuum ports or hoses on your engine. When you're modifying your intake system, removing emissions equipment, or cleaning up your engine bay, you'll often end up with open vacuum lines that need to be properly capped to prevent air leaks. This cap is made from a durable material that holds its shape and creates a solid seal.

HKS is known for making well-built performance parts, and even small items like this vacuum cap reflect that attention to detail. It's designed to fit snugly onto a 4mm hose or port, ensuring that no unwanted air can enter or escape the system. This is important for maintaining proper engine vacuum, which affects everything from idle stability to sensor readings. Using a reliable cap like this helps prevent potential check engine lights or drivability issues caused by vacuum leaks.