Anti Freeze coolant in the bulge

Hi all,

During the boating season I had noticed that I was get coolant containing anti-freeze into the bulge with no loss of coolant to the port engine. Each time I checked I was unable to find any leaks coming from the port engine. Untill at weekend when I noticed that the close coolant expansion tank for the port engine was full to the top. The boat has not moved from its berth and the engine has not been started for a few weeks. whilst unscrewing the expansion tank the coolant came out under pressure and the coolant was cold.
Further investigation and after speaking to Colin Camburn for a second oppinion the cause has now been traced to the calorifier of which the heating coil is fed from the port engine. It appears the heating coil has a pin hole or micro crack which will explains the cause for excess coolant in the closed coolant system and also contamination to the pot water system which will now have to be cleaned and flushed thoroughly.
I have now sourced a new calorifier which will be changed out in the next couple of weeks.

Yep, nightmare John I have seen that before. In most cases it will leak that way since your domestic water pressure will usually exceed the pressure in the engine closed circuit cooling system when cold and pressurise the header tank (as you have realised!!).
Clearly makes for a real headache anyway.
Nick

Hi Nick,

I have heard of other boat owners on other forums with a similar problem with excess coolant, but now realise what would cause this. The Plumb Centre deal with Albion who produce marine calorifiers and at a good price. The other option is to order a Surecal calorifier which comes with all the fitments including a hot/coldmixer valve to prevent the hot coming out of the tap at 80 degrees C.

Will be changing out the calorifier for a larger capacity and may add accumulators to the hot and cold lines. I am thinking 4 litre accumulators should be ok going by the 10% rule.