Tried & Tested - Bustin' barnacles

All large marine diesels with heat exchangers, fuel coolers, intercoolers and gearbox oil coolers require a constant and uninterrupted flow of raw seawater to transfer heat away from the engine components. The cooling water is then flushed out to sea with the exhaust.

However, the quality of the raw water, its temperature and the mixing of hot and cold water over metal surfaces within the heat exchanger causes many types of deposits to form, which degrade the performance of the cooling system.

So what happens when the raw cooling system of a large marine diesel is disturbed by the buildup of scale, salts and even little molluscs?
The answer is an overheating engine and, in fact, my Mariner 43 recently suffered the indignity of having its heat exchangers blocked with all forms of salts and Crustacea.

ENGINE MUSSEL FARM
In addition to the mussel farm in my engine, salt had built up in the 2in pipes leading to and from the heat exchangers, thereby restricting 50 per cent of the
raw water flow.

In hindsight, it was no wonder that both engines’ temperature at cruising speed had risen past 90?C during the summer months.
Drastic action was called for, so I turned to three very interesting products.

The first couple of engine-flush products are chemical blasters of anything that contains calcite or salt, and the third is a less expensive product that neutralises or dissolves salt in the cooling passages of an engine.
I also bit the bullet and made some plumbing modifications to the cooling system to make further cleaning a breeze.

THE PROJECT
This was always going to be a one-week project that involved the removal of pipes going to and from each of the heat exchangers on my Detroit 8V92s.
I last did this four years ago and swore at the time I would make it easier the next time around.

The
brass pipes (pump side)
were taken to ENZED Fittings where ½in water-injection nozzles were installed in each.
These fittings were later connected to some rubber hose and a ball valve.
I then injected the cleaning solution into my raw-water pipe and pushed it through the heat exchanger.
Water exiting the heat exchanger would be routed back to a bucket where a small bilge pump circulated solution in a continuous loop.

(Top Tip: It’s really important to ensure there are no leaks, otherwise the solution will drain away before it has time to carry out its work.
Test the system for five minutes for leaks before adding the expensive chemical).

THE PRODUCTS
The traditional approach was to remove the heat exchanger and dip it in an acid bath.
Nowadays, the heat exchanger can be left in situ with several specialist cleaning products available, two of which also compete against each other in the industrial and machinery market — Barnacle Buster, and Rydlyme.

The third product I tested is called Salt-X, neutralising salts already in suspension that also make
physical salt deposits move into suspension.
Salt-X competes against other brands such as Salt Away and Volvo’s Neutra Salt.

Over the past four years I have used both Rydlyme and Barnacle Buster on my own engines to clear the salt deposits, scale, shells, mineral buildup, dirt and the remainder of old zincs.
I can tell you that both products work.
Each of my own engines required about 10lt of mixed solution to fully circulate and
the solution was still concentrated enough to do the second engine.

Rydlyme’s technical sheet shows hydrogen chloride to be an active ingredient whereas Barnacle Buster uses phosphoric acid.
It should be mentioned that both manufacturers add in some other ingredients to make their total product.
Both products are biodegradable, safe to dispose of and do not harm the environment.

My tests showed both the solutions remain active for up to 24 hours and this can easily be tested by dipping a sea shell into the solution and seeing if it starts to dissolve.
If your heat exchangers are completely clogged, then the process may take three hours or so.

My heat exchangers seemed to be clear after two hours of having the solution pumped through.
In fact, it was fascinating to see what happened when the Barnacle Buster solution was added to the circulating water… there was a huge amount of gas bubbles given off from the heat exchanger as the chemical started to work.
This settled down after a few minutes, but the clear water turned dark brown.
Obviously strong stuff!
(The Rydlyme solution turned almost black).

Barnacle Busters price is about $150 for 5lt of solution mixed 4:1.
Rydlyme charge $80 for 5lt with a ratio mix of 50:50.
I now intend to use these products whenever I see my engine temps rise again, or every two years, now I have my injection system operational.

SALT BEGONE
Salt-X is a flushing product that removes or neutralises salt.
The solution is super concentrated and a nifty dispensing applicator ensures the correct dosage is applied for outboard and inboard engines.

You will see I have modified my own engines to inject Salt-X once every month or so as I
certainly don’t want my pipes blocking up again!

In many cases, Salt-X is all that’s required to keep a heat exchanger clean, however, this can greatly depend on the raw-water quality and seawater temperatures.

Inject the solution into petrol inboards or outboards when shutting down.
Price is about $144 for 10lt of a concentrate that makes up 35lt of solution.
Other Salt-X products have different concentrations and are used to protect fishing reels and other equipment from salt damage or washing down the boat.

FINAL WORD
The results of using both Rydlyme and Barnacle Buster saw my cruising temperature reduce immediately from 92degreesC down to a respectable 83degreesC, which is about where the Detroit Diesel guys like to see them.

To clean my heat exchangers I paid $150 in chemicals and about $70 in fittings and labour.
I was quoted more than $4000 to have this done by an opportunistic marine mechanic a few years back.
The maths of these products stacks up.

WEB CHECKLIST

Barnacle Buster at www.stellasystems.com.au

Rydlyme at www.rydlyme.com.au
Salt-X at www.salt-x.com.au

You will find good product details and technical sheets for various applications.
I do suggest you read them to find out how to inject the solution in the easiest manner.

Photos: Salt-X SX50 neutralises and removes salt residues; No need to remove the heat exchanger with Barnacle Buster; Check out the amounjt of build-up that occurs.