Engine Cooling System Maintenance

[pmyatt]

Friends of ours with a 4 cylinder Solé diesel (marinised Mitsubishi) have just had the engine lifted out for repair because of water in the oil. The problem seems to have come from a set of four blanking plugs between the block and the head; perhaps put in when the engine was converted to a marinised fresh water cooled version? When these plugs corroded through, the fresh and sea water system were able to mix, but this does not explain how the water reached the oil, unless it travelled from the water galleries to an oil gallery at the head/block interface? Additionally, although the heat exchanger tubes were clear, the dismantled heat exchanger body was filled with a soft rust-coloured clay-like deposit.
At a cost of approx. £ 2000, this is all going to be rectified but, it raises a general question; just how much maintenance do people do on their cooling system; do they check block/head anodes regularly, heat exchanger contents, both tubes and body, flush both fresh water and sea water side of cooling systems with de-calcifier, flush with rust inhibitor, etc., etc. I know I have not been doing this - but sure as hell are going to look at it now!!!!!!

 

[pvb]

I change the coolant at recommended intervals, otherwise rarely touch the cooling system. I had the 20-year old heat exchanger off for the first time a couple of years ago as part of another repair and had it checked and cleaned, but it was basically OK as removed. Unless there's a particular problem, I don't like the idea of running strong acids through the engine.

 

[Otter]

I agree about the acids. I drain and refill the fresh coolant twice a year and add DC4A to prevent cavitation corrosion and inhibit corrosion. Otherwise just a good dose of antifreeze with the autumn empty/refill. Same time I wash through the stack, takes 5 minutes; I was amazed this summer when we changed the oil cooler that so much weed had got through the Vetus raw water strainer.