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What is the correct way to drain a BMC 1.5 for winter?


Guest Cattleya

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In the past I have always popped a heater under my engine over winter, but since I now have a nicely rebuilt engine I was thinking of doing a proper drain down over the worst of the winter months. It then dawned on me that I don't have the slightest idea how to do this. My engine is not raw water cooled, so I guess it's only the heat exchanger to drain? Is there an easy way to do this?

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Your heat exchanger will normally have a drain bung at its lowest part, also remove the raw water hose at it's lowest point (turn off seacock) unless the boat is being lifted in which case just leave the seacock open and it will drain out. It can sometimes be difficult to get all the water out, especially upstream of the heat exchanger and exhaust injection elbow. Many people (me included) do none of the above but just turn off the seacock and itroduce anti freeze into the system via the weed strainer with the engine ticking over. If you go down that route make sure you use environmentally safe antifreeze.

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In the past I have always popped a heater under my engine over winter, but since I now have a nicely rebuilt engine I was thinking of doing a proper drain down over the worst of the winter months. It then dawned on me that I don't have the slightest idea how to do this. My engine is not raw water cooled, so I guess it's only the heat exchanger to drain? Is there an easy way to do this?

We've been doing what David suggests for many years with total success. From a Sabb 2GZ, through a Volvo TAM D 41P to a Nannl 50. they all respond well! :clap:clap

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Cattleya, that's exactly what we did last winter and as it was our first winter as a boat owner wanted to do it right, and we carried on boating through all the bad weather,just avoid the ice though,it makes a mess of your paint! :cry

Andy

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  • 4 weeks later...

Winterisation needs to be done properly - every time. The one time you skimp may be the one time you replace your engine or have to rip your boat to bits to replace a ruptured tank that's locked between bulkheads....

Engines.

Introduce antifreeze into the whole engine - you really need to ensure that it's up to temperature so that the thermostat is open. Some of our fleet boats get air into the calorifier circuits when you drain them down to get antifreeze in; ensure that you remove all this air when you top up as pockets will ensure that untreated water remains in loops which could cause problems. Also remember to put antifreeze into the exhaust circuit.

Showers & sinks

Many sinks have water traps or swan-necks in pipes. Pour antifreeze down drains to prevent freezing.

Many showers have pumps. Pour antifreeze down drains to prevent pumps freezing.

Toilets.

Many flush with river water. Turn off sea cocks and introduce antifreeze into the flushing circuit until it appears at the toilet.

Water tanks.

Drain all tanks - leave taps open - disconnect pipes at the water pump and, ideally, at the exit from the tank also

Remove soft furnishings and store in dry place ashore

Disconnect gas bottles but do not allow regulators to sit in water.

If the boat is left in the water, you'll need a good battery to ensure thet bilge pump remains operable. However, ideally, remove all other batteries and store ashore and charge them regularly else you may end up with £100+ bill for new ones in 2011.

There's plenty more to do too and it all depends on your attitude to risk and space ashore for storage.

If anyone needs help with winterising, Freedom offers a comprehensive service.

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Your heat exchanger will normally have a drain bung at its lowest part, also remove the raw water hose at it's lowest point (turn off seacock) unless the boat is being lifted in which case just leave the seacock open and it will drain out. It can sometimes be difficult to get all the water out, especially upstream of the heat exchanger and exhaust injection elbow. Many people (me included) do none of the above but just turn off the seacock and itroduce anti freeze into the system via the weed strainer with the engine ticking over. If you go down that route make sure you use environmentally safe antifreeze.

Useful info. When introducing antifreeze via the weed strainer how long do you tick-over for and how much antifreeze do you intoduce? It might be that you tick-over for, say, 20 seconds and introduce a constant stream of antifreeze during that time. Also, my strainer is at the back of the boat, far from the helm, and to turn the engine off after inroducing the antifreeze would mean a short period of time where the engine was just ticking over with no anti-freeze being introduced (it would probably take about 30 seconds to get out of engine well and back to the helm to stop engine). Would this mean that the anti-freeze would all be pumped out? Perhaps I have to work with a help mate? On the other hand would it be sufficient to fill the strainer to the brim and then just run the engine for 20 seconds or so?

Finally, where can I get "green" anti-freeze and is it expenive?

Many thanks.

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In the spec for your motor somewhere will be the raw water capacity they vary from motor to motor obviously, just use a bit more than that, plus whatever you estimate is in the inlet hose. It is best to have a mate ready to turn off the engine and as the whole job only takes a couple of minutes it’s not much to ask of a neighbouring boater or such (you can always offer to return the favour). Unless your strainer holds about 10l then you will have to introduce it manually :naughty: . Green A/F can be bought from Wroxham Marine I believe, if you can access your exhaust outlet with a bucket to catch the water then you can use cheaper stuff of course. Make sure you have everything ready and to hand before you start.

A couple of other thoughts; it may well be worth using the same method when you decommission to put some “Redlyme†through the raw water side, this will clean out any scale and deposits in the stacks and improve and maintain cooling efficiency.

Some more sophisticated engines may require that they are run to temperature before introducing A/F or Redlyme as they have thermostats which direct the raw water through the oil cooler only after working temperature has been reached in order to get the oil warm as soon as possible to reduce wear. Not an issue on your average broads cruiser but may be present on some later, larger lumps and it’s not a good idea to inhibit the system if the oil cooler stack doesn’t get done too as the last thing you want is water in your oil. Remember that some motors have numerous stacks, including but not limited to Coolant heat exchanger, Engine oil cooler, Transmission fluid cooler, Charge air cooler and return fuel cooler.

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Unfortunately I am no engineer and the manual is confusing me (what I have of it). My engine is a Perkins 4.108. It has raw water cooling and cooling via a radiator/water tank. The radiator is not a problem as it has anti-freeze in it. What I cannot find out is the capacity of the raw water side of the cooling system. can anyone help?

Many thanks

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The question seems to have been well answered on here now, but just coming back on a detail,

I like to set myself up so that such jobs can be done single-handed, so with an engine that's some distance from the controls, I'd find out how to stop it at the engine itself, or fit an additional switch to enable that.

A BMC 1.5 marine diesel is stopped via a cable operated depressurizing valve (usually), so it may be possible to just pull on that lever on the engine, keeping hands and cuffs clear of any moving belts etc. ! :)

Alternatively, on one of my previous boats fitted with secondary cooling, I permanently fitted a tee piece on the hose between the inlet seacock and the engine and ran a short spur of hose down into a plastic 1 gallon container, with an on off valve. Then whenever I wanted to fill the system with antifreeze, I just put a gallon of pre mixed antifreeze in that container, then, just before switching off, I closed the seacock and opened the second valve and let the engine run until the container was empty, then switched off the engine and shut the valve again.

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Many thanks to you all cheers . I am now armed with a gallon of "green" antifreeze from Wroxham Marine (not premixed) and it only cost £12 :grin: . This together with a length of tubing to assist with feeding the antifreeze into the sytem means I am tooled up and ready to go.

Thanks again.

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In the end I went for a 135w tube heater under the engine (on a thermostat set to 4c). I intend to use the boat for a bit yet, so wanted something quick and easy. I have drained the domestic water down and will probably put some antifreeze through the raw water side of the engine if it looks like the temperature will drop well below freezing for more than a day.

Electricity seems reliable in the marina and there are a number of liveaboards around to reset it if it gets tripped.

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