Dirty/brown/orange colour cooling water

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Dirty/brown/orange colour cooling water

Postby 1moley » Wed Jan 02, 2019 11:11 pm

Hello all,

We have two auxilliarys that before drydock and full overhaul were filled with distilled water and unitor cooling water treatment. Post overhaul both have the same problem.

Post major overhaul we are now using hard shore water.

Since the overhaul almost immediately water has turned dirty/brown/orange colour. Before DD water was always clean.

We have various things checked by the outfit who overhauled them for leaks but nothing has been found. The system runs a LT/HT mix with a plate cooler on the LT circuit. Other side of plate cooler is LT again which is completely clean.

Pressure tested water cooled exhaust manifold, air cooler, Checked pumps, thermostat valves, changed all heads again. Cylinders are always dry on head removal.

We have flushed the cooling system through various drains around the cooling circuit until water run cleans. Circuit capacity is >100ltrs and have flushed maybe 5m3 over the last few months. Once engine runsm within 5mins water is back to the same dirty water.

Has anyone had anything similar or ideas to try?
Thanks in advance

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Big Pete
Engineering Mentor
Posts: 868
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Dirty/brown/orange colour cooling water

Postby Big Pete » Fri Jan 04, 2019 10:07 am

Possibly while the system was drained down for the overhaul work, the insides of all the cooling system corroded and this is now coming into the cooling water.
Unitor /Wilhelmsen etc make a commissioning cleaner for de-greasing and de rusting new pipework systems, maybe a power flush with that followed immediately by filling with treated water, so no time for corrosion to form while the system is drained down.

Good luck and let us know how you get on.

It is always better to ask a stupid question than to do a stupid thing.

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