This vehicle has long suffered from a blowing head gasket. The symptoms were that under sustained load, say up a hill, bubbles would appear in the water, displacing so much that the engine would boil over. Luckily, water did not get into the oil.
Being a side-valve engine, changing the gaskets is very simple. We started by doing a compression test, and all 8 cylinders were showing 8.0-8.5 bar, so no clues here. We decided to do both sides, and clean and paint the engine at the same time. Water drained, hoses removed, and 21 nuts removed from each side, and off came the heads.
It does look good, and when the paint has dried properly, we can torque down the heads and give it a run.