Cleaning calcium out of cooling system

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tobble

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Had great fun motoring home (no wind /forums/images/graemlins/frown.gif ) at 1.5 knots over the weekend. the problem was that at medium and above revs, the water alarm went of. to cut a long story, tied up and removed all the accessible cooling hoses and cleared out a pile of a calcium type deposit, one of the elbows was completely blocked!

anyway, I'm still slightly worried that the channels in the head are bunged up, and was wondering about pumping some vinegar in to break it down. any thoughts?

oh, it's a Yanmar 1GM10 by the way (raw water cooled)
 
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Had great fun motoring home (no wind /forums/images/graemlins/frown.gif ) at 1.5 knots over the weekend. the problem was that at medium and above revs, the water alarm went of. to cut a long story, tied up and removed all the accessible cooling hoses and cleared out a pile of a calcium type deposit, one of the elbows was completely blocked!

anyway, I'm still slightly worried that the channels in the head are bunged up, and was wondering about pumping some vinegar in to break it down. any thoughts?

oh, it's a Yanmar 1GM10 by the way (raw water cooled)

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That or cycle Furnox through it ?
 
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pumping some vinegar in to break it down

[/ QUOTE ] Vinegar is too weak. An acid based cetral heating boler descaler will be better. Sbc suggests Fernox but they make a wide range of products and he does not say which one. Fernox DC-3 is an a acid based descaler but there are others and other makes. Hydrochloric acid (brick cleaner) is the final resort measure perhaps. It will be quick but it is not inhibitted to prevent attack on the metal and could therefore do some expensive damage.

Take a look at the boiler descalers in your DIY stores and plumbers merchants and try to find one containing sulphamic acid. That is stronger than organic acids but now where near as strong as hydrochlorc acid.
 
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make sure you also flush the sea water outlet too . it can furr up with salt water crystals deposited when the hot water evvaporates when engine shut down

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Personally - I would be inclined to fill a bin with furnox or other Central heating system additive and connect to seawter inlet ... run engine to pump it through sytem and out normal exit - ie exhaust ! It can also be collected for return to first tank for repeat flushing through ....

My engine rec'd a fresh water flush other day ... took top of strainer ... lifted out gauze ... started engine then put garden hose into top of strainer ...
Initial water out was black with soot and crud ... then soon ran clean.
 
My son swears by swimming pool cleaner for removing these deposits from marine air conditioning and refrigeration units. As suggested, best way to use is to recirculate from a container from beneath the exhaust.
 
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I'm not an engineer but I wonder if Calgon would be any good

[/ QUOTE ] Obviously not a chemist either! No calgon is used to prevent scale forming but would not remove existing scale.
 
My thoughts as well. I've had these deposits in my 1GM and as they occur around the inlet pipes and the internal anode, I think they are mostly zinc salts. The flexible pipes and adjacent bits I've always cleaned out mechanically, not having the courage to pump any form of weak acid into an aluminium block, but vinegar is probably the right thing to use. I usually flush the engine through with fresh water at the end of the season as well. Someone on this venerable forum once suggested that antifreeze (glycol) would help clear it, but I can reliably report that all it does is turn the salts blue! /forums/images/graemlins/frown.gif
 
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furnox or other Central heating system additive

[/ QUOTE ] Fernox do a whole range of central heating system additives including boiler noise reducers, corrosion inhibitors, scale preventers, sludge removers, leak sealers and antifreeze as well as descalers.

Only the descalers DS40 and DS3 are going to be of any use to tobble.

DS3 is in fact the one which contains sulphamic acid and would be my first choice. It also contains a coloured indicator that shows when it is exhausted.

Other makers of course do similar products.
 
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they occur around the inlet pipes and the internal anode

[/ QUOTE ] The chemistry involved does tend to lead to deposits of calcium carbonate around anodes. With impressed current systems a large build up ususally indicates that the system is being over proteceted (current too high) If it is zinc compounds building up then maybe it is zinc carbonate, or more likely zinc oxide. The other common salts of zinc are soluble.

Vinegar or dilute acetic acid would be useful as a regular flush through to prevent scale build up but it would take a long while I suspect to remove a heavy build up.

You are right to be cautious though with aluminium blocks or heads. The Fernox DS3 is said to be Ok with aluminium components in good condition DS 40 is i believe based on organic acids, presumably stronger ones than acetic acid, so might be a better choce if there is any doubt about the suitability of DS3.
 
Sulphamic acid without a doubt is the best - used in industrial boiler cleaning. Its a weak acid but will bind or chelate with a variety of sulphates, chlorides and oxides of different metals - unlikely to be calcium around more likely to be sodium from sea water = salt.
As the salt water cooled engine is getting hot this makes matter worse, as salt water is LESS soluble in hot water rather than cold (or warm) which is why the optimum temperature for raw water cooled engines is 50 degrees centigrade. Sulphamic acid will not attack or degrade aluminium, stainless cast iron, copper etc but will attack salts which is why it is best
 
I think I might try this stuff as well, then but not until she comes ashore next winter. According to the website:
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Fernox DS-3 contains Sulphamic acid and is classified as irritant. Irritating to eyes and skin. Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment.

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So flushing the engine through on the mooring might not be a friendly thing to do.
 
Sulphamic acid is biodegradeable. By the sounds of things you need to pickle the engine over a week to clean out the heat exchangers, and then flush through with fresh water over the weekend
 
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As the salt water cooled engine is getting hot this makes matter worse, as salt water is LESS soluble in hot water rather than cold (or warm)

[/ QUOTE ] If you are trying to say that sodium chloride is less soluble in hot water than in cold water then I think you are wrong. 35.7gramms per 100cc at 0C and 39.12grams per 100cc at 100C!
 
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As the salt water cooled engine is getting hot this makes matter worse, as salt water is LESS soluble in hot water rather than cold (or warm)

[/ QUOTE ] If you are trying to say that sodium chloride is less soluble in hot water than in cold water then I think you are wrong. 35.7gramms per 100cc at 0C and 39.12grams per 100cc at 100C!

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He's also wrong about why it deposits ... according to Perkins ... Raw water engiens are run cooler than Heat Exchange engiens because .... when engine is stopped and is at temp. the water evaporates leaving behind the salts in the channels ... so running temp is kept slightly below temp that would cause serious deposits ..... An engine with Heat exhanger fresh water passing through can run at higher optimum temp.

Of course any fault / change in conditions can push the engine temp over that lower limit ...
 
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Ooooh! I know I may regret this

[/ QUOTE ] It sounds avery sensible thing to do!
 
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when engine is stopped and is at temp. the water evaporates leaving behind the salts in the channels

[/ QUOTE ]That is something I have not heard before. I far as I knew sea water cooled engines are run at a lower temperaure to reduce the rates corrosion and scale deposition. Cheifly the scale formation I think.
It is very difficult to imagine that much of the water evaporates from a closed environment, it would have to boil and in that case you would expect to see a significant rise in the temperature reading soon after the engine is stopped. You do get a small rise I suppose but not enough to suggest that the water is boiling.
 
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