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32-3 Coolant recovery tank

Filkee

Sustaining Member
This is is my coolant recovery tank: 5D87A8E2-2EB7-4334-8920-6C4D629CBC45.jpg

Is there anything magically marine about it or could I replace it with something from the car part mart? I see things like it for $10, but when I add “marine” to the search everything is $59. The failure point is the cap and I’ve been killing myself for a year trying to a replacement.
 

markvone

Sustaining Member
View attachment 26440

The failure point is the cap and I’ve been killing myself for a year trying to a replacement.

Rust holes in the metal cap?

I used a piece of an aluminum can (beer, soda, pop) cut in a circle and placed inside to block the rust holes in the cap top. That was 8 years ago.

You may be able to find a replacement cap from another bottle, can or jar. Plastic would provide a lifetime fix, but my original metal cap lasted 30 years which just may be my remaining lifetime.

Mark
 

Bolo

Contributing Partner
Amazon

This is is my coolant recovery tank: View attachment 26440

Is there anything magically marine about it or could I replace it with something from the car part mart? I see things like it for $10, but when I add “marine” to the search everything is $59. The failure point is the cap and I’ve been killing myself for a year trying to a replacement.

Here is the one I used as a replacement on my 32-3. Easy and cheap.

https://www.amazon.com/gp/product/B000E35UV2/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
 

bgary

Advanced Beginner
Blogs Author
I added a coolant/expansion tank to my 32-III as part of the replace-the-fresh-water-pump project.

I used a simple tank from the local auto-parts store, 10 bucks plus-or-minus. It hangs on the bulkhead just inside the engine cover, which puts the bottom of the tank just slightly above the cap on the manifold.

Since this photo, I have added a couple of blue-tape marks, one indicating the level when cold, the other indicating the level when the engine is warm. By doing this I can tell at a glance if my coolant level is nominal, or if something is potentially amiss. (blue tape so I can easily move the marks when I add or change coolant)

FWP%2003%20running%20(s).jpg

Bruce
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Interesting. It's not what I think of as an expansion tank, which is a simple overflow/suck-back-in tank, usually plastic.
 

markvone

Sustaining Member
The metal (pressurized) tank with the sealed radiator type cap is the expansion tank. This provides space for heated water to expand into. The plastic, non-pressurized tank is the overflow tank. A hose runs from the top of the expansion tank goes to the bottom of the overflow tank. My expansion tank cap doesn’t have a spring for over pressure, it just flows coolant into the overflow tank and then sucks it back under vacuum when needed.

Where does the black hose at the metal tank cap go? Mine goes to my overflow tank. Looks like This one goes to the bilge.

Mark
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Got it: recovery/overflow tank vs. expansion tank.

Now, why don't I have a remote pressurized expansion tank like that. ?
 
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Cory B

Sustaining Member
Expansion Tank

We had a metal "Expansion Tank" and removed it 10+ years ago with no problems. The only useful thing I think it did was create a convenient High point to bleed the system when changing coolant, and there are other ways to accomplish that. Our expansion tank was located inconveniently in the lazarette which is part of the reason I took it out.

We still have a simple plastic overflow container.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
The hoses from our expansion tank go to / from the hot water heater - - I'm wondering if a hot water heater requires the expansion tank, and boats that don't have a water heater may not need the expansion tank. Just wondering why some have it, others don't. :confused:
Frank
 

Joliba

1988 E38-200 Contributing Member
Frank,
I don’t think that the hot water heater is the reason. We have a hot water heater but only have a non-pressurized overflow reservoir tank. (I also recently replaced mine with the same simple tank from an auto parts store as others here have posted.) As I understand it, the expansion of the coolant causes the overflow. So, I too am curious about the function of the additional metal tank.
Mike Jacker
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
So then does anyone have an explanation for why some of our boats have both a metal expansion tank with pressure cap and a plastic overflow tank with a nonpressurized plastic cap, while others have only the plastic overflow tank? There must be a reason why someone thought we needed both on some of our boats. All the metal tanks look the same, so I'm thinking they came from the factory that way.
Frank
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
I have an identical setup to Filke. I can't find any literature on it, but from my "new-purchase" research, I had the distinct impression the expansion tank was required due to the fresh-water heating function of the Raritan water heater.

Why? I don't think it said so explicitly. My guess would be because a "radiator" cap is normally located at the high point of the coolant system to allow any overheated, boiling coolant to escape as a gas (steam), out the cap. When a water heater is added, there in now a lot of fluid located higher than the pressure-relief cap on the manifold. Overheating in this case would cause a considerable loss of liquid coolant from the cap, rather than just the blowing-off of a little steam.

So, the expansion tank moves the pressure relief cap back to the high point of the system. Why the tank has to be so large, I have no idea.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Ok, that all sounds logical. However, some boats have water heaters but no expansion tank. How do they manage, without spraying coolant when the pressure rises?
Still a mystery, I think. ☺️
Frank☺️
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
On both my boats the water heater is/was much lower than the engine coolant pressure cap. No remote expansion tank fitted.
 

Joliba

1988 E38-200 Contributing Member
This makes some sense now. So, I suppose those with hot water heaters located higher than the pressure cap on the engine may have difficulty bleeding the coolant system if the have removed their metal tank. Perhaps they would need to bleed the system while the boat is heeled!!?? And filling the system would be a challenge if the filling points are not higher than the rest of the system.
 
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