Thought I would pass on the fitting I pieced together at Home Depot and used for flushing my engines and adding antifreeze today. I have been looking for a suitable cap for my strainers to facilitate running antifreeze into the engines but they don't seem to be made anymore. I was going to try and make a fitting from scratch using PVC and was looking for a PVC cap to get started. I happened on to the "Test Titan Mechanical Test Plug" stocked at Home Depot in the PVC fittings shelves. It is something of a compression fitting and fits into PVC pipe; the red ring tightens to secure the plug into the pipe. It has garden hose threads at the top; I had to drill out the top because it comes closed. The 3 inch PVC male adapter fits my strainers perfectly (Groco 2000/2500). I used a short hose attached to the top with the other end in a bucket of antifreeze. Worked like a charm and made the process much easier. Total cost was $7.41 counting a bit of retired military discount (thanks Home Depot for offering that).