Descale inboard diesel

[parkstone bay]

Hi
My little MB has a Bukh DV24, which I consider to be a brilliant little engine, but after 15 years, it's clear that it's beginning to scale up internally (raw water cooled). Has anyone ever used a household kettle descaler to remove salt encrustation; if so any recommendations?
(Note: 1. I would block off the pump, and remove hoses and thermostat, so that any acid/aggressive chemicals didn't attack rubber parts. 2. I do occasionally fresh-water flush the system - but probably need to do this more frequently).
Finally, the Block is cast iron; and, as I'm in the UK, I need a UK-available product.
Thanks everyone!

[a64pilot]

Pretty sure that rubber hoses shouldn’t be effected, paper gaskets I’m less sure of.

[Lepke]

Barnacle Buster is on Amazon,co.uk.
https://www.amazon.co.uk/Trac-Ecolog...3373320&sr=8-2

[Compass790]

Originally Posted by parkstone bay

Hi
My little MB has a Bukh DV24, which I consider to be a brilliant little engine, but after 15 years, it's clear that it's beginning to scale up internally (raw water cooled). Has anyone ever used a household kettle descaler to remove salt encrustation; if so any recommendations?
(Note: 1. I would block off the pump, and remove hoses and thermostat, so that any acid/aggressive chemicals didn't attack rubber parts. 2. I do occasionally fresh-water flush the system - but probably need to do this more frequently).
Finally, the Block is cast iron; and, as I'm in the UK, I need a UK-available product.
Thanks everyone!

You can use spirit of salts ( hydrochloric acid )25% & then flush with baking soda. There are youtube vids on this. Works in 20mins.
I tried the vinegar but it was hopeless. CRC rust remover works too if you want a commercial product.

[Wotname]

If you go the aggressive approach (acid etc), do remove the zinc anodes in the engine first. In fact, I would remove the anodes regardless of what method you use. Don't forget to refit them .

Note the "salt" build up is actually mostly calcium carbonate and that is what you are trying to remove.

[OloteleMtn]

When i pulled the head of the engine on the boat I had bought recently, the cooling passages were completely plugged. I used a mixture of muriatic acid, commonly used for concrete cleaning, and water, at a more or less 50% acid to water ratio. Don't breathe the fumes, rinse well afterwards.

[Wotname]

For the OP, muriatic acid is also know as hydrochloric acid. It is fairly aggressive but works well. As suggested by Compass790, I would recommend a final rinse of bicarbonate of soda if using an aggressive acid.

[a64pilot]

I don’t flush with baking soda, I figure running the motor flushes it very well with just plain sea water, but of course flushing with soda doesn’t hurt, and if it were a fresh water system is needed, but as it’s raw water it gets very well flushed.
My opinion is muratic acid, (pool acid) also (concrete cleaner) is very effective and very reasonably priced, a good run immediately after the acid will flush it well, just don’t let the acid sit for days without running the motor.

[parkstone bay]

Thanks to all for your comments. Some really good stuff there!
My Scottish ancestry has always preferred "least cost" solutions, and it looks like I should be able to do the job without breaking the bank.
Thanks again.

[Don C L]

My buddy uses a product we have here called CLR (calcium, lime and rust remover) which may be the same descaler you have there. He has a Volvo MD7A. He put in a "t" in the raw water intake hose and periodically runs the engine with the thru-hull closed and running the CLR in through the T. It seems to work for him.