Cool system

[Steelboat]

Can anyone explain how this cool system works , see attachments
Thank you

[Lepke]

Guessing somewhere on the engine is a heat exchanger.
The pump sends water to the engine HE. Some of the water goes out with the exhaust. Excess water goes out the 2" pipe. Either the exhaust water or the 2" pipe water is controlled by a valve.
On some engine/pump setups have an excess water valve. Too much water in the exhaust can overwhelm any water muffler, so some goes directly over the side.

My mains have this setup. I had to rotate your pic. Old man tired eyes.

[Steelboat]

Thanks for the information, l will be over at boat tomorrow, take a few more photos, maybe establish is it a heat exchanger.
Next question will be how to antifreeze.
I seen mechanic just screw off water filter cap at pump, turn off valve , and turn engine until pink freeze spits out the back ??
Might be too late , l arrived first night freeze , bay heater had activated but 3 buckets water in engine bay.!!
Talk tomorrow if about

[Steelboat]

Ps
When l say seen mechanic antifreeze technique that was a few years ago.
I now do it myself

[rls8r]

Your boat engine's cooling system works very much like your car's cooling system. There's the water that circulates within the engine block that removes heat from the cylinders. But then, there's another, separate water system that removes heat from the engine block water. In your car - the heat is removed from the engine block water by the radiator - which uses a fan to draw (relatively) cool air over a series of tubes through which the hot engine block water passes. Excess heat is removed by heating the cool air.

In your boat engine you have the (fresh) engine block cooling water that you fill via either the radiator cap on the reservoir or an expansion tank (which I don't see in the pictures of your engine). You'll have a pump on the engine that circulates that water throughout the engine. It may be below the fresh water reservoir and out-of-sight in the pictures of your engine. It will be run by a 'v' belt on your engine's crankshaft pulley. You put antifreeze in that system just like you would in your car.

You'll also have a 'raw' (salt) water cooling water system. That system is a flow-through system that gets its water from below the boat. It comes in through a thru-hull fitting, passes through a filter and enters a heat exchanger. The raw water pump is also driven by a 'v'-belt off the crankshaft pulley. Yours is the one to which a green elbow and hose are attached.

That cool raw water circulates around a series of tubes inside the heat exchanger through which the hot engine block water passes - being pumped by the engine water pump. The now-hot raw water exits the heat exchanger and is (usually) introduced into the exhaust system through an exhaust elbow before the muffler. The excess engine heat is removed by heating the raw water in the heat exchanger jacket.

You add antifreeze to this cooling water system just as you describe. Shut off the thru-hull valve, open the top of the filter, start the engine, and add antifreeze to the filter until you see the antifreeze coming out of the exhaust pipe. Otherwise, you can take a hose off the filter and have the engine pump antifreeze from the jug it comes in or from a bucket.

The engine cooling system shouldn't have frozen if you've only had a day or so of below-freezing temperatures if the boat is still in the water.

[Steelboat]

Originally Posted by rls8r

Your boat engine's cooling system works very much like your car's cooling system. There's the water that circulates within the engine block that removes heat from the cylinders. But then, there's another, separate water system that removes heat from the engine block water. In your car - the heat is removed from the engine block water by the radiator - which uses a fan to draw (relatively) cool air over a series of tubes through which the hot engine block water passes. Excess heat is removed by heating the cool air.

In your boat engine you have the (fresh) engine block cooling water that you fill via either the radiator cap on the reservoir or an expansion tank (which I don't see in the pictures of your engine). You'll have a pump on the engine that circulates that water throughout the engine. It may be below the fresh water reservoir and out-of-sight in the pictures of your engine. It will be run by a 'v' belt on your engine's crankshaft pulley. You put antifreeze in that system just like you would in your car.

You'll also have a 'raw' (salt) water cooling water system. That system is a flow-through system that gets its water from below the boat. It comes in through a thru-hull fitting, passes through a filter and enters a heat exchanger. The raw water pump is also driven by a 'v'-belt off the crankshaft pulley. Yours is the one to which a green elbow and hose are attached.

That cool raw water circulates around a series of tubes inside the heat exchanger through which the hot engine block water passes - being pumped by the engine water pump. The now-hot raw water exits the heat exchanger and is (usually) introduced into the exhaust system through an exhaust elbow before the muffler. The excess engine heat is removed by heating the raw water in the heat exchanger jacket.

You add antifreeze to this cooling water system just as you describe. Shut off the thru-hull valve, open the top of the filter, start the engine, and add antifreeze to the filter until you see the antifreeze coming out of the exhaust pipe. Otherwise, you can take a hose off the filter and have the engine pump antifreeze from the jug it comes in or from a bucket.

The engine cooling system shouldn't have frozen if you've only had a day or so of below-freezing temperatures if the boat is still in the water.

Thats a brilliant explanation of how it works.
Just one question ...in paragraph two you talk about an expansion tank ( which you cannot see)
Is that not the tank you see on photo and the one and only place l add antifreeze ??
Or have l missed something.( very possible)
I will take a few more photos today and that might help .
I was following explanation really well until the missing expanasion tank .
I seem to think l should have two places l add antifreeze, according to your writeup.
More photos will help today
Thank you

[Steelboat]

PS
One other question, what is the 2 inch orange pipe in photo that runs from engine area or heat exchanger to the bottom of hull

[Steelboat]

Please find attachments ris8r
Hopefully these photos explain all to you

[Steelboat]

Some more photos

[rls8r]

Good morning, Steelboat -

The small white-ish tube that exits at the fresh-water cooling reservoir cap (looks like a 'radiator' cap) and leads below the engine is your overflow tube. It usually leads to a plastic expansion tank (look at your car's engine and note that you add water/antifreeze into a plastic tank instead of directly into the radiator - that's your car's expansion tank), but in your case it seems to simply drain into the bilge. So - you only have one place to add antifreeze to the fresh-water engine block cooling system.

I note that you seem to have a gate valve on the salt-water intake line (if that's what it is). Gate valves are not the best thing for thru-hulls since they have a tendency to either sieze-up from corrosion or leak. You may want to think about replacing the gate valve with a ball valve at some point.

What kind of (make/model) engine is this?

I don't see a 2" orange pipe in any of your photos (but then, my eyesight isn't what it once was). Which photo shows the pipe you're talking about? When you say "pipe" - do you mean "hose"? When I hear "pipe" I usually think of something made of metal; when I hear "hose" I usually think of something made of plastic or rubber.

I'm off to my boat now. I'll check back later today or tomorrow. Good luck with your winterizing.

[Steelboat]

Clarification ..
Small 10mm hose pipe beside cap ( over flow pipe) runs to bilige like you say.

The 50m pipe ( orange pipe in my hand made drawing) runs from centre of exchanger to boat floor ( lake)

I understand how water is sucked up from belt driven pump , connected to y joint on exhaust and cooling system.
I understand engine has totally enclosed water/ antifreeze ststem.

I do not understand what the 50mm hose running from centre of heat exchanger is doing or how it works in conjunction with intake .( runs to lake / floor
It has no filters, so l assume kicking water out or some sort of overflow .??

[Steelboat]

Will attach my hand drawn photo with orange 50mm hose to boat floor/ lake

[Steelboat]

Ps
Boiler fed off this engine for hot water !!

[rls8r]

I'm afraid that I can't help you solve that mystery. I can't think of anything that would need a 2" (50 mm) hose (at all). Usually, hot water feed lines from engines to water heaters are 5/8" or 3/4" and they don't (in my experience) come from the heat exchanger.

Larger hoses (say 1-1/4" or 1-1/2") leading to thru-hulls are generally for sink or cockpit drains. Are we sure that the 50 mm hose is clamped to a fitting on the heat exchanger?

Again - what make/model engine did you say this is? Perhaps we can look on the Internet for a service/parts manual.

Hope someone else on this forum can provide some information. Sorry.

[Steelboat]

Thanks for the feedback, its a mystery.
It could be 1 1/2 inch or there abouts.
It goes from the hull floor into the heat exchanger around the middle area.on heat exchanger.
The engine is a damilier/ merc om 352-900-0

The engine also has 2 hoses leaving the engine area running over to hot water tank