cutoff valves and raw water cooler questions

[jkallen21]

Hey guys - 2006 SANTE with the raw water cooler option.
1. I’ve always wondered which valves go to which. In the little hatch door where the drain plug is, there are 4 valve handles. One is red, 3 are green. I assume the green ones are ballast and the red is for the engine. But I’d like verification from someone who knows better than me.

2. I have the raw water option in the boat, but I’ve never really understood what that is and how it works. I’d love an education on how it works vs a boat without it.

Thanks!

[NautiqueJeff]

Normally, the red valve goes to the engine, but trace the hose just to be sure.

From your previous posts, it looks like you have a ZR6, which is NOT raw water cooled. It is fresh water cooled.

Raw water cooling is the standard cooling for most engines of that era, except for the ZR6. RWC pulls water from the lake, and runs that through the engine to cool everything.

Fresh water cooling is where the engine uses automotive style anti-freeze to cool the engine, and only uses raw water from the lake to run through a heat exchanger to cool the anti-freeze, and also for cooling the exhaust & transmission. Engines with fresh water cooling have fewer components that need to be drained at winterization.

Here's the ZR6 water flow / cooling diagram from your engine manual:

[jkallen21]

Thanks Jeff - and you're correct. I do have a ZR6 so it sounds like I do have the Fresh water cooled engine (I recognize the large oval looking tank at the 1:00 position in the diagram). From the diagram, it seems that during winterization, I only need to worry about draining the places with the "star" indicator? Thanks!

[NautiqueJeff]

Yep, that's correct.