Raw vs fresh

I have to replace the exhaust

I have to replace the exhaust manifolds on my 1998 7.4. I have some people saying I should install a fresh water system while I am going through all this work.

Pros/cons?

"Are you replacing the risers?

"Are you replacing the risers? If you are running in fresh water then I would not change to FWC until repowering.

FWC helps keep the engine temp. stable for better fuel atomization and engine operation. It protects from freezing in the winter.

If you boat in salt water you would need to install a full FWC system that cools and protects the block, exhaust mans. and risers or you're wasting your money since the salt will destroy the mans. and risers soon.

Once you install the FWC system you will need to run a strong radiator cleaner to flush out the rust from the block and change the antifreeze 2 or more times as the rust is broken loose and suspended in the solution."

"Even in a full FWC system, th

"Even in a full FWC system, the risers (elbows) will be raw water cooled... the goes 'outta from the Hx goes to the risers and overboard with the exhaust. There will be a gasket between the manifolds and the risers (elbows) with the coolant passages blocked off to keep the two water paths seperate.
If there are spacer blocks (which I think Guy is referring to as 'risers') between the manfolds and the elbows, those will be fresh water cooled."

"Thanks for the clarification

"Thanks for the clarification Troy. "