What antifreeze for raw water?

I think most antifreeze are much the same. Some come ready mixed, usually a 50/50 mix and some are concentrated. The general rule seems to be not to mix different types. They are coloured, often pink, blue or green. If in doubt, flush the system and start from scratch.
 
Just use whatever is left over from the coolant circuit/van/car! (Just don’t mix colours, as suggested - can form a chemical sludge). I go for a 50% mix assuming it’ll dilute a bit with water already in the system.

As an aside, I also wash off the hull (it runs down the topsides) as I worry it could stain.
 
Just realised that you're asking about the raw water side, which begs the question, how do you propose to use coolant in a system that is constantly flushing water through the system? Am I missing something? The freshwater system is a closed system, like you have in a car, but the raw water set up usually just draws raw water in (from whatever you're floating in) and passes it through the block, eventually exiting with the exhaust. Maybe I'm just having a brain fart!
 
sogood said:
Just realised that you're asking about the raw water side, which begs the question, how do you propose to use coolant in a system that is constantly flushing water through the system? Am I missing something? The freshwater system is a closed system, like you have in a car, but the raw water set up usually just draws raw water in (from whatever you're floating in) and passes it through the block, eventually exiting with the exhaust. Maybe I'm just having a brain fart!
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As an antifreeze for winterisation (required in these parts!)... first flush the system with freshwater and then run sufficient coolant/antifreeze through to fill the system (heat exchanger mainly)
 
RJJ said:
Hi - to protect the raw water side, is there any particular antifreeze required? Or just the cheapest available which seems to be

Odessa Red Antifreeze & Summer Coolant Concentrate For All Engine Types- 5L x 2: Amazon.co.uk: Business, Industry & Science

Appreciate the need for the right coolant on the freshwater side.

Thanks!
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D2-55 ?

Follow the procedure for draining the sea water system and flushing with an antifreeze mixture described in your owners manual.

It would make sense to use the same type of antifreeze as you use as the engine coolant rather than have two different types kicking about
( I believe that will be an OAT type ( usually red or yellow) for recent versions but a conventional low silicate type ( usually blue or green ) for older versions )

(When the coolant is changed perhaps use the old coolant to flush the sea water side)
 
MartynG said:
If you do feel the need to use toxic chemicals please consider how it will be prevented from entering the aquatic environment.
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Not the worst thing to get into the sea:

Ethylene glycol is readily biodegradable in standard tests using sewage sludge. Many studies show biodegradation under both aerobic and anaerobic conditions. ... Ethylene glycol has generally low toxicity to aquatic organisms.
Source WHO.

Just keep it away from your child or your dog The antidote is vodka apparently
 
As my boat is lifted clear of the water during haul-out, I ask for the lift to be halted for a few minutes. I remove the sea water strainer lid and have a bucket of fresh water available. A pal starts the engine and I pour water, jug full at a time, into the strainer. As the bucket is almost emptied, I change and pour ready mixed antifreeze into the strainer, about 3-4 litres, then stop the engine. The cheapest that I’ve found is £1 per litre from Pound Shops, perfectly adequate.

At the start of the following season I replace the impeller. Removing the pump cover, there’s always a lot of antifreeze in evidence so I’m happy to conclude that this process flushed away sea water in preparation for winter hibernation.
 
I use the stuff which is safe for drinking water systems on the basis that I understood the ordinary anti freeze to be highly toxic in the marine environment.
 
Thanks.

Yes it's for winterisation and corrosion protection while she is laid up. On or off the water.

Upon first start in the spring, I will do as per this year and catch the first bucket load of liquid coming out of the exhaust for proper disposal. I do try hard not to poison our fishy friends.

Thanks. All good suggestions. Sounds as though cheapest is best.
 
VicS said:
D2-55 ?

Follow the procedure for draining the sea water system and flushing with an antifreeze mixture described in your owners manual.

It would make sense to use the same type of antifreeze as you use as the engine coolant rather than have two different types kicking about
( I believe that will be an OAT type ( usually red or yellow) for recent versions but a conventional low silicate type ( usually blue or green ) for older versions )

(When the coolant is changed perhaps use the old coolant to flush the sea water side)
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Any hints on volume required? Many thanks
 
Robih said:
I use the stuff which is safe for drinking water systems on the basis that I understood the ordinary anti freeze to be highly toxic in the marine environment.
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The propylene glycol based antifreeze you are using is in fact just as toxic to aquatic life as ethylene glycol based antifreeze . It's just not toxic to humans and other mammals
 
Freezeban non-toxic, otherwise don't let it discharge onto the ground or into any waterways. We al use the same planet and need to look after it, antifreeze is harmful to just about everything that as sailors, we enjoy.
 
Moodysailor said:
Freezeban non-toxic, otherwise don't let it discharge onto the ground or into any waterways. We al use the same planet and need to look after it, antifreeze is harmful to just about everything that as sailors, we enjoy.
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Freeze ban is propylene glycol based. There is therefore little advantage in using it from an environmental point of view
 
...Or fit/use a drain plug in the exhaust water trap? That’s logically the lowest point in the system and could be used to capture the majority of the antifreeze safely before recommissioning and assuage any environmental concerns.
 
Personally if you're winterising an engine, I think it's important to drain the exhaust and disconnect it from the injection elbow, so you are not exposing the innards of the engine to damp air for months.
If you do that, it's just as easy to drain the seawater lines and heat exchanger, so there's no need to sod about with antifreeze.
Ideally, take the end off the HE and see if there's any crud, bits of impeller etc in there, but alternatively just flush it with fresh water and suck the water out with a wet vac. If you think there will be too much water in the HE, then plug one of the seawater hoses and fill it with AF solution via the other one.

It's goodto know your HE is clean.

For the sake of undoing a few hose clips, it's a lot less pantomime and no need to put glycol etc in the harbour.
 
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