Converting to closed cooling system for 94 Ski Nautique w/ 351 ProBoss

[Dan30]

I am wanting to install a closed cooling system in my old Nautique so I can extend my ski season. NautiqueParts says the PCM doesn’t offer a system for that motor. It should be mostly standard parts I’m thinking, just the routing of the fresh water into the exhaust manifolds could need some mods? Any ideas?


Sent from my iPhone using Tapatalk

[gary s]

What do you hope to accomplish? thinking you'll not have to winterize?

[SilentSeven]

Here's what we did - installed a quick drain kit on the block, manifolds. If you don't have a heater, you can drain the engine in minutes. If you do have a heater, you'll need to pull the hose and blow out the line (typically easy to do when the engine's warm and the hoses are soft). I never want to see another drain plug in my life...these are sooooo easy.

You can [uh oh...used to be able to] get the kit here: https://skidim.com/maintenance/engine-drains.html I'd call them and ask...they used to offer a 4 or 5 drain kit for about $80 that had two block drains, two manifold drains and a elbow pipe drain. Looks like now they sell them by the item.

[Dan30]

Yes I don't want to worry about freezing in the early and late seasons. I had thought about drain valves, but will be installing a heater kit this winter. Even with the closed system I suppose you would still have to drain the heat exchanger and the exhaust manifolds.


Sent from my iPhone using Tapatalk

[gary s]

And drain the trans cooler and strainer as well,and don't forget the sherwood pump will be full of water too. Here is PCM's parts breakdown sheet for the Freshwater cooling. The hard parts to find is the Y number 14 in the pic and thermostat and housing 15,5 and 6. The heat exchanger and header tank are off the shelf parts made by several different companies. Being in Canada makes a hard job finding parts even harder. I do not feel that converting would be your answer

[scottb7]

Being in Minnesota, I thought much about this issue and concluded that no matter what it was too cumbersome to drain often.

So what I did was buy a couple of heaters. I put them out when I thought temp would drop below freezing for extended periods of time. I was able to put each of them on different circuits so if for whatever reason one failed and blew a breaker I had the other one still going. If you have access to power or extension cords maybe consider this. For me it was only an issue a couple weeks on each side of the season.

I used below referenced. Xtreme heater is super nice and very reliable. I tested it few times. Davis air dryer is nice because absolutely no moving parts to worry about.

Choosing the Best Boat Engine Compartment Heater for You – Xtreme Heaters

Amazon.com: Davis Instruments Air-Dryr 1000 Dryer : Automotive

[NautiqueJeff]

Even with closed cooling, you'll still have to winterize. This doesn't really accomplish what you seem to think it does. You'll still need to drain the heat exchanger, exhaust manifolds, etc.