KAD43: Flushing out coolant

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Folks,
Friend who has a 2 x KAD43 engined boat wants to completely flush out the coolant - don't ask me why, don't think they know when it was done last so want to do so now.

Question: One engine has a calorifier. Am I right in saying that flushing out a cool engine (ie. thermostat closed) won't flush the whole system, as there will be a section blocked off by the thermostat.

2nd question: If answer to above is 'yes', is the calorifier on the hot side too, so that won't be flushed out?

3rd question: If answer to both above is 'yes', is the best way to do a 'full' flush out, either to bring the boat for a run so thermostats are open (how long do they remain open for?), or remove the thermostat to completely flush out?


Any tips much appreciated. I have a service manual for these engines on a crashed hard drive which I haven't had a chance to see if I can claw data back on yet

 

[volvopaul]

Look at front of engine, bottom left side you will see two black hoses tied together, the one with the blue tie is the sea water drain , the other is from the lowest point of the engine block, pull out bung to drain block. There is also a plug on underside of heat exchanger to drain that too. Easiest way to drain hot water tank circuit is to remove both hoses and pump with dinghy pump to blow out coolant or flush with hoses pipe.

 

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Thanks for the reply Paul. We've already done as you mention above. Our concern is on the 'other' side of the closed cooling system (ie. behind the thermostat) - We'll do as you say, un-do the calorifier pipes and blow through