Worked well to get my 2006 Volvo Penta 4.3Gi engine maintaining coolant again. I had to remove the front engine mount to replace the front freeze plug. I started them with a socket resting against the edge then tapped them in place with a smooth face hammer in the center of the plug. Online they said you shouldn t hit them in the center but that was the only way they went in. The fit was fairly snug.
I bought these to install in a marine engine, they are needed for marine systems. The only problem I see is that the large plug is not brass, it appears to be steel.