Tweco Water Cooler Sight Glass Cap Replacement

Keep Your Cooler Running Leak-Free

If you are running a water-cooled TIG or MIG setup, you know that the water cooler is the heart of your thermal management system. The sight glass on your Tweco cooler is there to give you peace of mind—a quick glance tells you the coolant is flowing. However, if the cap on that sight glass cracks or gets lost during a fluid change, you are looking at a messy leak and potential downtime. The Tweco 4120-2013 Sight Glass Cap is the direct replacement you need to get back up and running.

Don't risk using makeshift plugs or generic caps that might strip the threads or fail under pressure. This is the authentic Tweco part, designed to screw on perfectly and seal tight. It holds the sight glass assembly together, keeping your coolant where it belongs—circulating through your torch, not dripping on the floor. Whether you are refurbishing an older unit or just fixing a cracked cap, this part is the simple solution.

Maintenance is part of the job, and having the right small parts makes it easier. Swap out that old, yellowed, or cracked cap with a fresh one to ensure your flow indicator is clear and secure. It’s a small investment that protects your expensive torch and cooler pump from the issues caused by leaks and low fluid levels.