I have a 1998 Volvo Penta 5.0Gi freshwater that is freshwater cooled in my 240 offshore. As fas as i know they are the original manifolds and risers i have owned the boat for 5 years now and im concerned about the life expectancy of them the boat is used in saltwater almost always.I know that the saltwater comes out of the heat exchanger and then to the manifolds so they are subject to the salt just like a raw water cooled motor. Is there any way to test them (obviously i will need to remove them) or inspect them? Any suggestions on different manufacturers of them or oem i have had no problems but dont want any unecpected ones either. i think im on borrowed time with 14 years on them! any comments welcome