Inboard engine winterization

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Posse

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How much antifreeze should I expect to use to winterize the seawater cooling system, including exhaust hose and water trap?

Also, should I use concentrated or mixed antifreeze?

My engine is a Volvo Penta D2-55 fitted in a 42' sailboat.

(I am aware that I can see at the exhaust when the antifreeze starts coming through, but I would like to know approximately how much I need for the operation)
 
How long is a piece of string? Suggest you mix up a 5 litre container 50/50. Use a watering can to put it into open strainer with engine on tick over and get someone to shout when it comes out blue or red from exhaust. Stop filling switch off and keep remainder for next year. Works ok for me.
 
Halo said:
How long is a piece of string? Suggest you mix up a 5 litre container 50/50. Use a watering can to put it into open strainer with engine on tick over and get someone to shout when it comes out blue or red from exhaust. Stop filling switch off and keep remainder for next year. Works ok for me.
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So, on your boat 10 litres is more than enough that could be a good starting point for the OP
 
Not sure why you would want to fill it with antifreeze. Why not just drain it and leave it empty? Any water in there is seawater which is unlikely to freeze unless the boat is in a very exposed position in a very cold part of the country. The all important freshwater system should have a coolant mix in it which is also an antifreeze.
 
Well, this is Denmark. It can get down to -20°, and the water is not very salty.
Also, there is no way to drain the system completely, especially the exhaust and water trap.
 
Posse said:
Well, this is Denmark. It can get down to -20°, and the water is not very salty.
Also, there is no way to drain the system completely, especially the exhaust and water trap.
Click to expand...

Your profile is silent as to your location. A few basic details can be useful to those offering advice.

The usual method of emptying a water trap is to disconnect it and tip the water out.



Tranona said:
Not sure why you would want to fill it with antifreeze. Why not just drain it and leave it empty? .
Click to expand...

The owners manual does recommend filling with antifreeze because the system is difficult to drain fully.
 
VicS said:
The owners manual does recommend filling with antifreeze because the system is difficult to drain fully.
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Yep - Kindred Spirit's trap had a drain plug, but in her installation it was almost impossible to reach. Ariam's trap has no drain. Last winter I took the exhaust elbow off for inspection and cleaning and, since we would be out of the water over the coldest period, took the opportunity to tip a couple of litres of non-toxic antifreeze down the hose into the trap.

Very hard to answer the OP's question though, because almost all the relevant volumes depend on his particular installation (specifically the lengths of hose) rather than the engine.

Pete
 
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Posse said:
Well, this is Denmark. It can get down to -20°, and the water is not very salty.
Also, there is no way to drain the system completely, especially the exhaust and water trap.
Click to expand...

On a much smaller engine and boat (20 hp/9 m) I normally use a 50/50 mix of 4 liters in total, which is plenty.
Last winter I had bought only 1 liter of glycol, so used 2 liters in total and also had no problems. The most sensitive bits of piping must surely be the heat exchanger and anti siphon? Seawater pump and connecting hoses perhaps get drained when you take the impeller out for inspection? If you have the Volvo type of water trap (rubber and stainless steel) I doubt freezing water would harm it and exhaust hoses would normally be empty in most installations.
Consider using propylene glycol, which is less harmful to the water environment than the other type (unless you collect it next spring).
 
That was why I stated the size of the boat. I think most modern sailboats have the engine under the cockpit ladder, or in that area, roughly a third of the boat length from the rear, and with the exhaust about at the rear end of the boat, usually without substantial detours for the hose. So, for a general rule-of-thumb amount of antifreeze, that should be quite easy to state for anyone who tried this himself.
 
Thank you - that was very helpful :) I will put 4-5 liters of mixed antifreeze through then.

BabaYaga said:
On a much smaller engine and boat (20 hp/9 m) I normally use a 50/50 mix of 4 liters in total, which is plenty.
Last winter I had bought only 1 liter of glycol, so used 2 liters in total and also had no problems. The most sensitive bits of piping must surely be the heat exchanger and anti siphon? Seawater pump and connecting hoses perhaps get drained when you take the impeller out for inspection? If you have the Volvo type of water trap (rubber and stainless steel) I doubt freezing water would harm it and exhaust hoses would normally be empty in most installations.
Consider using propylene glycol, which is less harmful to the water environment than the other type (unless you collect it next spring).
Click to expand...
 
Generally:
Drain as best you can.
Fill with plain water.
Drain as best you can.
Fill now known (tidal) volume with what ever mix suits you.
If you think there was a lot that wouldnt drain, up the ratio a bit, if you dont freeze that hard, lower it a bit.
 
Posse said:
How much antifreeze should I expect to use to winterize the seawater cooling system, including exhaust hose and water trap?

Also, should I use concentrated or mixed antifreeze?

My engine is a Volvo Penta D2-55 fitted in a 42' sailboat.

(I am aware that I can see at the exhaust when the antifreeze starts coming through, but I would like to know approximately how much I need for the operation)
Click to expand...

I have never flushed (with antifreeze mix) the raw water side of an indirectly cooled engine, only checked the engine coolant has the correct 50/50 mix and never had a problem.
Virtually all the raw water drains out when the boat is lifted out for the winter.
I have only flushed a directly cooled engine when lifted out for the winter.
If the boat is staying afloat all winter then no need to flush at all unless in an exceptionally cold region like the arctic.
 
My boat is out of the water at Inverness Marina.
A quick google search suggests that Inverness regularly sees -10deg C and -17deg C is not unknown. Minimum recorded in the hIghlands is about -27 deg C.
The Comma data sheet for Super Coldmaster, Mono Ethylene Glycol antifreeze (Blue) say a 33% mix gives protection down to -18 deg C and 50% down to -36 deg C.
So when I flush the seawater side of my engine next week, I'll use a 50% mix, perhaps a bit less, and I know that a 2 gallon (about 10L) bucket full will do the job on my Yanmar 4JH4E.
 
An added consideration is that many boatyards do not allow engine running after liftout which means flushing with antifreeze mix becomes problematical unless the boat is towed to the lift.
 
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Posse said:
Well, this is Denmark. It can get down to -20°, and the water is not very salty.
Also, there is no way to drain the system completely, especially the exhaust and water trap.
Click to expand...

When you stop the engine, all the water in the system downstream of the engine drains into the water trap/silencer - that is what it is there for. However it will not be full as its capacity is greater than the piping. When you remove the impeller, the complete seawater system drains because the anti syphon valve lets air in. So there is only a very small amount of water left. Even if you put anti freeze in, it will only sit in the bottom of the water trap - nowhere else.
 
MS gearboxes on the VP MD17 series of engines do not completely drain when the boat is ashore so it is vital to flush with antifreeze or gearbox housing cracks. See thread about this problem. May apply to other engines with raw water cooled gearboxes
 
Tranona said:
When you remove the impeller, the complete seawater system drains because the anti syphon valve lets air in. So there is only a very small amount of water left. Even if you put anti freeze in, it will only sit in the bottom of the water trap - nowhere else.
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I find that a bit sweeping, must it not depend on the engine model? On mine (Beta 20 hp) the heat exchanger certainly is a low spot in the cooling circuit, made worse by the tilt towards the stern.
 
Kurrawong_Kid said:
MS gearboxes on the VP MD17 series of engines do not completely drain when the boat is ashore so it is vital to flush with antifreeze or gearbox housing cracks. See thread about this problem. May apply to other engines with raw water cooled gearboxes
Click to expand...

I think the VP MD17 is a raw water cooled engine (not indirectly cooled) so should be flushed with 50/50 mix anyway if wintered ashore so the gearbox would be protected.
 
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