mercruiser 3.0

[oteps]

Oil pressure sending unit was leaking a little. Previous owner had the adapter break so he put a brass nipple in the block and then a brass nut then sending unit. Not sure of the brass nut name but its like a butt connector in the plumbing world. Should I leave it alone and just reseal it or buy the correct adatper?

Also a block water plug was leaking a little so I tried to turn it to check if it was tight and it broke. Replace blue plastic plug or replace with a brass block plug?