Best thing for removing salty crud from coolant passages?

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fredrussell

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Working on a mates Dolphin engine thats sat for a bit. Runs but no coolant flows. On removal of head easy to see why - completely bunged up.

What do people use to clear this stuff please? Its just the head so easy to submerge it completely if need be.
 
fredrussell said:
Working on a mates Dolphin engine thats sat for a bit. Runs but no coolant flows. On removal of head easy to see why - completely bunged up.

What do people use to clear this stuff please? Its just the head so easy to submerge it completely if need be.
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I assume from the suggestions made that the cylinder head is not an aluminium alloy. I know of Dolphin engines but nothing about them.

My personal preference would be for a weaker acid than hydrochloric acid . A sulfamic acid based descaler such as Fernox DS-3 perhaps http://www.fernox.com/products/water+treatment+chemicals/limescale+remedies/limescale+remover+ds-3
 
Eco friendly acid toilet bowl cleaners usually are Lactic and sulfamic acids pretty safe or regular Toilet bowel is hydrochloric 9 % safer to use than harsh muratic acids like brick cleaners
 
seaangler23 said:
I've used coca cola on outboards but probably need something a bit stronger for that
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Coca Cola is effective because it contains citric acid. The concentration is quite low so a large volume of would be required to remove more than a small quantity of scale .

However Fernox DS-40 System cleaner is mainly citric acid and would be a good choice where Coca Cola is not quite up to it but it is a weaker acid than the sulfamic acid in DS-3
 
Sea Q said:
Eco friendly acid toilet bowl cleaners usually are Lactic and sulfamic acids pretty safe or regular Toilet bowel is hydrochloric 9 % safer to use than harsh muratic acids like brick cleaners
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Muriatic acid is an old name for hydrochloric acid which is the "active ingredient" of some, but not all, brick cleaners. Limescale removing toilet bowl cleaners are a somewhat more dilute solution ( up to about 10% HCl).
 
Rydlymn should be safe, going to flush my engine this year...

http://www.qflush.com/engels/products/rydlyme-marine

The exception to number 9 above, when using 100% concentrated (non-diluted) RYDLYME Marine on magnesium, zinc, and/or some alloys of aluminum, it could oxidize or pit. Furthermore, polished chrome and some alloys of stainless steel could become discolored. The rule of thumb is that if the alloy is designed for use in a water system (aluminum engine block, aluminum mold, etc.), the alloy should be compatible with the RYDLYME Marine solution. Otherwise, it is recommended that the RYDLYME Marine be diluted 50% or more with water when cleaning.
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Not sure I like the 'should' bit there mind you...
 
sailorman said:
Hydrochloric acid / brick cleaner / rydlime
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I second brick cleaner. From B&G is cheap and correct dilution. Not too dangerous but not too diluted either. Also available from car spares shops as wheel cleaner. Watch contact with paint and rinse out very thoroughly. Leave engine running in a drum of fresh water afterwards
 
If the water passages are completely blocked, its gonna take some long time for the acid to come into contact with the salt and therefore longer for it to attack the metal of the head. I'd try some mechanical method as well like a long screwdriver or similar. Also you could test out the acid on a non important surface of the head first to make sure thers no adverse effect. Or (just thinking aloud) how about coating the machined surfaces of the head with something like candle wax first to protect it against damage from the acid.
 
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