Over the last few months I’ve noticed that every 2-3000 miles the coolant level in the expansion tank has been dropping by approximately 25mm. I’d looked everywhere for the source of this unknown leak for a while before someone on the forum mentioned that where the top hose connects to the top of the engine, the elbow that the hose clamps on to can corrode causing a very slight leak on the underside of the hose which makes finding it very difficult due to the small amount of coolant involved and also that it tends to be evaporated away by the heat from the engine. The only tell-tale sign is a small amount of a ‘crusty’ pink-ish deposit on the underside of the hose.
With the leak finally found I ordered up the necessary parts to do the job, hopefully this weekend if the weather decides to be kind! I’ll post a write up in the next few days of how it goes.