Engine - raw water antifreeze or not?

[Tim O]

I live aboard and currently my engine is out of action due to faulty injector pump so i cant run the engine to pull an antifreeze solution through

The raw water system still contains some freshwater from its last use - would the best solution just be to drain all this out from the lowest point......i figured if i remove intake from pump and the hose from the anti-syphon break at highest point, then blow it through i can basically remove the majority of the water.

The coolant system should be fine as it has antifreeze in anyway.

So far i havent bothered as its not been so cold and Im onboard with heating on most of the time but may have to be away the next two days

 

[Tranona]

Highly unlikely to freeze. Is the water you are floating in freezing?

If you are worried no big deal to drain it as you described. I would be more concerned about the fresh water in your domestic system freezing though!

 

[vyv_cox]

Yes, won't do any harm. You have not told us what engine but on my Yanmar almost everything is rubber anyway, unlikely to be damaged by freezing. The heat exchanger drains itself.

 

[Tim O]

Beta marine 38

No the freshwater in the Marina is not freezing up at all at present....neither is the bit of water in the engine compartment bilge, from rainwater leaks

Yeah -slightly concerned about domestic freshwater system, but if i drain and replace all that with antifreeze it's kinda hard to live aboard!!

I do have a tube heater in the forecabin which i guess i could leave on with all doors open, and hope that will keep the whole boat above freezing point if Im away the next couple of days, though im never keen on leaving stuff on tbh

 

[BabaYaga]

......i figured if i remove intake from pump and the hose from the anti-syphon break at highest point, then blow it through i can basically remove the majority of the water.

I think the heat exchanger is the most vulnerable part (and most expensive to repair/replace).
If your Beta has the newer, three bolt end caps, then the zinc anode will be in the upper part of the exchanger, so that opening cannot be used to evacuate all the water.
If so, and especially if the engine is tilted aft (for shaft propulsion), there might be a small risk of water being left standing in some of the exchanger pipes, as they will form a kind of low point in the circuit.
You should be able to pour in antifreeze mix from the anti syphon hose and to replace any standing water if you took the impeller out, I imagine.