So half way back home with Helga I noticed the coolant level was just above the minimum line, then when I stopped to check it yesterday the header tank was empty. Filled it up and kept a close eye on it. It was using about a litre per hour’s driving, and the header cap was collecting sludge.
However, happy news for once! Having bought a head gasket kit I noticed a damp patch where the coolant lines enter the bulkhead. Turned out the hose had rubbed through on the alternator bracket, then been taped over with electrical tape. I drained and flushed the system, replaced those hoses with silicone from Babs, correctly adjusted this time to avoid the alternator. As a double check I popped the cam cover off to find no evidence of water in the oil so I’m going to see how she runs now.
As a bit of a treat I swapped the side indicators back to orange, replaced the bonnet badge and ground back and kurusted some of the surface rust from the inner wings. Also replaced the temp gauge sender so the gauge works now.