‘Most instances of overheating are caused by fouled props, undersize skin tanks or expansion tanks’
FOLLOWING MY ADVICE on adding antifreeze, a reader tells me Beta says it will not honour its warranty if a 50 percent antifreeze mixture is not maintained in the system. Apparently this is because Beta overheat alarms are set for between 95 & 100C and the engine needs that amount of antifreeze to raise the boiling point to over 120C.
I find the explanation somewhat perplexing, because the pressure cap on its own will raise the boiling point to over 110C; most instances of overheating on narrowboats are caused by fouled propellers, undersized skin tanks or insufficient expansion tank capacity for the coolant volume in use.
As antifreeze reduces the amount of heat the coolant can carry away, I would have thought having a high concentration would be more likely to cause overheating. But anyway, check your engine manual to see how much antifreeze you are required to use.