Eleanor Macson
New Member
Hello. New boat owner of a yacht with Yanmar 1GM engine on the hard with no access to water. Should I add antifreeze via running the engine for thirty secs pouring water and antifreeze solution in or give it a miss....?
Winterising engine
- Thread starter Eleanor Macson
- Start date
Fmurchu
Member
I have a 3gm30 and mechanic advised me to run some antifreeze through it. Its an anti corrosion as well. Just leave it start up and shut down again once started.
peter gibbs
Well-Known Member
Putting in sufficient anti freeze to the closed system to reach about 30 % should protect against Uk winter conditions. If a high frost risk area take it up to 50%. If you have to withdraw some of the old coolant via the topup first so be it. This is the bit that costs if attcked by frost. Run the engine briefly to circulate the mix, if necessary, but this is achieved when you proof the raw water system, next below. Dont assume that whatever's in there is up to winter strength. Pink antifreeze is the standard about £19 per 5 litre bottle.
To your specific Q-
The raw water system also benefits from a 30% winter fill. Start the engine and flush a few litres of fresh water into the open strainer using a funnel if necessary. Have 5-8 litres of mixed antifreeze to hand and pour this in after the fresh water. Stop the engine whilst the fluid level is still visible. Use the stop on the engine or have someone stop it on your command, leaving the system full of mix all winter long. Do not turn the engine during the winter or the a/freeze is lost for no other benefit. Close off the raw water intake before this operation to retain as much mixture onboard as possible.
Forgive me for pointing out the absolute need to have no gear that will drag your person onto the working engine! Rehearse what you're going to do and all will be well. I do this every year and great care pays!!
PwG
VicS
Well-Known Member
Unless you run the engine, recirculating the antifreeze , until it reaches full working temperature , your antifeeze will simply go straight through the bypass and out with the exhaust leaving the cooling sytem proper still full of seawater.
The OP should completely drain the cooling system via the cylinder drain cock and ensure that the water pump is also drained by removing the cover.
If she wishes to fill with antifrezze now run the engine with the pump suction in a bucket of antifreeze solution until all the antifreeze has been pumped in. It should now be full of antifreeze.
Perhaps a good idea to finally empty the water trap in the eexhast stem and cap off ( stuff a rag into ) the engine exhast ebow
VicS
Well-Known Member
The OP's 1GM10 is directly seawater cooled... ......There is no closed fresh water circuit which you a appear to be describing.
If the engine's ( seawater ) cooling system is flushed with fresh water and then antifreeze substituted virtually all the antifreeze will simply go through the by-pass and out of the exhaust leaving the engine block full of fresh water and an even greater risk of frost damage .
vyv_cox
Well-Known Member
Vic has beaten me to it but everything he says is correct. The OP's mechanic has given incorrect information.
A simpler method might be to drain the engine via the stopcock on the block, remove the thermostat housing assuming this to be the highest point on the engine, flush with a bottle of fresh water in the absence of a hosepipe supply, then close the stopcock and fill with antifreeze solution.
A simpler method might be to drain the engine via the stopcock on the block, remove the thermostat housing assuming this to be the highest point on the engine, flush with a bottle of fresh water in the absence of a hosepipe supply, then close the stopcock and fill with antifreeze solution.
johnalison
Well-Known Member
Running the engine on the hard can be a risk if the boat is not properly supported in a cradle or twin keels. Some boatyards still just use wooden props, which can be satisfactory if used properly.
VicS
Well-Known Member
The thermostat fits in horizontally from the front. Not so handy for flushing like that but using a funnel attached in place of the outlet hose on the housing might work
Eleanor Macson
New Member
Thank you everyone. For your considered responses. I shall mull them over and I might have to get some assistance! Much appreciated. 
VicS
Well-Known Member
On second thoughts . it wont work 'cos there's nowhere for the air to escape
vyv_cox
Well-Known Member
I did qualify my response as I don't know this engine. Thermostat is at the top of 3GM and the Bukhs.
LiftyK
Well-Known Member
Do check with your yard. In some running the engine ashore is not permitted, presumably to avoid vibration and risk of toppling. Whatever the reason, it's not permitted in my yard.
Before lift out next time, run the engine until it is hot. Motor to the lifting point. Stop the engine. Close the cooling water intake seacock. Use hot water or a hot air gun to release the pipe from the seacock. Connect a short joiner hose from engine intake hose to your bucket of antifreeze, using a hosepipe joiner. Preferably hang a bucket under the exhaust outlet to stop antifreeze going in the sea or river. Start the engine, run the antifreeze through then stop the engine. The 1GM uses very little cooling water so the whole operation is unhurried.
Before lift out next time, run the engine until it is hot. Motor to the lifting point. Stop the engine. Close the cooling water intake seacock. Use hot water or a hot air gun to release the pipe from the seacock. Connect a short joiner hose from engine intake hose to your bucket of antifreeze, using a hosepipe joiner. Preferably hang a bucket under the exhaust outlet to stop antifreeze going in the sea or river. Start the engine, run the antifreeze through then stop the engine. The 1GM uses very little cooling water so the whole operation is unhurried.
Eleanor Macson
New Member
Sounds like a good plan!
