Flushing the engine with acid.

[Thresher]

I've often read that raw water cooled engines become blocked with salt as they age. Does anyone know what kind of salt it is? ie. is it sea salt, sodium chloride or is it like the furring you get in a kettle which is I think calcium carbonate.
Are there any products that can be flushed through the engine when it is winterised? (i'm thinking of patio cleaner or hcl which would take care of any kettle fur). Is there anything that would dissolve sodium chloride?

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[starboard]

When I winterise my engine I run it for 30mins with the sea water pickup disconected and placed in a bucket that is being fed by fresh water. after about 30mins i stop the fresh water hose filling the bucket and add a 50/50 mix of fresh water and antifreeze. I stop the engine when I see antifreeze coming out with the exhaust water. If you do this the engine not only gets a good flush through but then has freeze and corrosion inhibitor to see it through the winter.

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[freebird1]

I recently used an automotive 'heavy duty' cooling system cleaner from Halfords.
My Bukh is raw water cooled too. I ran the enigne up to temperature, disconnected all of the external connecting pipes, blew them clear and with a small funnel, poured in the cleaner until it appeared at the next outlet. I left it half an hour, reconnected and ran the engine.
I was amazed at the amount of 'white' cooling water and particulates that came out of the exhaust, and the dramatic improvement in the volume of water coming through. The label said it was suitable for all metals in the system and would not affect rubber. Cost about £4.

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[seaesta]

Nice one.

I would only use such a proprietry item - and will try this

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[Thresher]

Thanks Freebird

I'll go down to Halfords and see if they list the contents on the container.

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[Mirelle]

Thank you; I'm on for that one too. I did a manual descale last year but I am sure I did not get all of it.

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[LeonF]

Why do you need to disconnect all the external pipes ? Do you mean hoses around the engine or ones connected to skin fittings ? is it to avoid the cleaner getting to the exhaust ? Please could you explain.

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[freebird1]

Sorry, Been away on holiday.
I disconnected all of the rubber hoses connecting the impeller to the block and thermostat and from the exhaust manifold (if you can call it that) to the exhaust injection point. This was for two reasons. 1, i could blow out the water still in the engine so that i did not dilute the cleaner, and two i could see when i had fill all of the available spaces (ie it trickled out of the next exit). Once full, i connected it all back together and left it. The just started as normal 30 minutes later and watched the debri coming out.

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[Trevor_swfyc]

I converted my Volvo penta 2002 to fresh water cooling about 10 years ago it had run on salt water cooling for 6 years previously. Last month I had the head of and salt deposits were still in the head, infact the spray bar outlets were all blocked.
I would suspect that if a channel is blocked by crusted salt deposits then no amount of flushing with either water or dilute acid will clear it. If you have no flow through a channel then it cannot contact the acid. Sulpuric acid diluted will attack salt but unfortunatly also the engine!

Take care.
Trevor

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