dragging mud through to the heatexchanger

[theendisgone]

my volvo 140 approx 1984 is dragging mud through into the heat exchanger and blocking it as it is in a fairly shallow canal does anyone know a remedy or maybe a kit that can be fitted to get the water a bit less deep also does anyone know a breakers for parts for this engine in the uk

and lastly the heat exchanger looks like a small plate has been pushed off at the bottom were it is domed can anyone tell me wether this was a plug or a fixed plate etc and how it can be rectified

thank you for your help