I have a 1982 2GM that is till raw water cooled. Have toyed with the idea of changing it to fresh water, but a few thing have kept me from doing it
1. cost. hate to spend $500 + on parts, when I may get a new engine in a few years, if anything big goes on this one.
2. Temperature - it has ran for 25 years at 130 degrees. Although diesels work better at 180 degrees, I am not sure it would like the change after all these years???
3. Not sure what pump to use. I thought I read that the rubber impellers (in raw water pumps) are damaged, or swell up, from antifreeze (when preparing for winter). Canm someone shed some light on whether it's best to get a new pump for the raw water (and use the old one for antifeeze) or vice-versa. if so, what type / model pump would be a good choice? I can't tell by pics which are shaft driven, and which can have a pulley on them!
4. where to find a heat exchanger. How to size one? Or, would an oil cooler work?
Call Jim or George at Depco Pump in Clearwater. They are familiar with the pump. They also have a service department that can re-build it for you very reasonably.