Removing Caravan Radiator/sludge

[BigRooster]

I’m going to remove one of caravan central heating radiators because it’s cold
at the bottom warm at the top so I’m thinking sludge the only thing I’m worried about when I drain the rad is how much of my antifreeze I may lose any advice please .

[EDDIE51]

You should drain the entire system flush it and refill it with clean water and new rust inhibitor/ antifreeze solution ! This should be done once a Year !