I posted previously about my Discovery 1V8, carb model, losing coolant and the difficulty of finding the problem. In a previous post I mentioned noticing that one of the cylinders had exceptionally clean spark plug compared to the others which were all sooted up. This has led me to remove the cylinder head on the right bank and finding no gasket! So I have started a head overhaul and will re-grind valves etc.

I looked at the inlet manifold today which has two pipes connected to it which go to the heater, those were corroded so I removed to clean. On cleaning up it one end of the longer pipe I found a pinhole as can be seen in the photograph. This will be enough to let out a small amount of coolant which will quite easily disappear down the back and the engine and would be difficult to spot as a leak. I’m not certain this is the only cause of losing coolant but clearly it is a culprit and almost impossible to spot. So if you have a mystery V8 leak worth checking between the engine and the bulkhead where this pipe connects to the heater matrix.