I purchase two additional covers for my Groco raw water strainers and drilled and tapped them to add hose fittings.
When winterizing the Cummins engine and the 6KW generator engine, I simply remove the regular covers from my Groco raw water strainers, screw in the modified covers, connect a short piece of garden hose with female connectors on both ends to the modified strainer covers and to a faucet in a 5 gallon bucket into which I have placed the antifreeze and then start each of the engines in turn so as to pump the antifreeze completely through the engine, hoses, mufflers, etc.
This new system really worked great this fall. At the same time, I thoroughly clean each of the raw water strainers as well. I have a similar connection on my heat pumps so that with one hose connection, I can pump antifreeze through these units as well. This approach saves considerable time and prevents spillage of antifreeze in the bilge of the boat.
Dick & Mable Seymour
Sea Mischief – NT 32-144