Decided to clip everything together tightly, then add coolant and see what happened.
What happened was that the tank filled up to half way, then there was a sudden glugging noise and the level dropped rapidly. I could hear liquid dripping and then pouring out, but when I got the light onto where I had been working, no obvious liquid despite the continuing noise. So I topped it up again, and after a couple of seconds the same thing happened.
And then the penny dropped .. I'd left off the expansion tank return wedged under the a/c pipes to keep it out of the way, and it was brimming over and coming out of there from the block and pouring onto the undertray past the starter motor. What a numpty!
After an internet outage it is possible to post that I've done a test run and got it up to temperature both locally and a drive to town and back, and I haven't expired on the side of the road in a cloud of steam ; fingers crossed I've resolved this one so far.
What happened was that the tank filled up to half way, then there was a sudden glugging noise and the level dropped rapidly. I could hear liquid dripping and then pouring out, but when I got the light onto where I had been working, no obvious liquid despite the continuing noise. So I topped it up again, and after a couple of seconds the same thing happened.
And then the penny dropped .. I'd left off the expansion tank return wedged under the a/c pipes to keep it out of the way, and it was brimming over and coming out of there from the block and pouring onto the undertray past the starter motor. What a numpty!
After an internet outage it is possible to post that I've done a test run and got it up to temperature both locally and a drive to town and back, and I haven't expired on the side of the road in a cloud of steam ; fingers crossed I've resolved this one so far.