Used this project for a few brief journeys just enough to warm the engine up despite often below freezing temperatures. Soon sees steam out from around the bonnet when you pull up and stop. This is what I saw when that happened. A jet of steam appearing to come from the Radiator Core or, more hopefully, from the Coolant Hose. The Fan was running at high speed so blows away the leak effectively disguising where the coolant leak is coming from. :~
View My Video
Later, with the powerful fan not operating, clearly the leak is from the short top hose attached to the T-Piece.
View My Video
So I will not need a new Radiator ... that's good news. Here's the problem. Could that be the prime reason for coolant loss in previous ownership? Loss leading to Cylinder Head Gasket damage from resultant overheating. Your guess is as good as mine but, it certainly wouldn't help.
It pays to lift car bonnets on scrapyard visits and having done so, I had a couple of good used spares including a pretty blue one. :~
I did not use that one...
Keen eyed observers will spot the OE Manufacturer's alignment Indexes on the hose are not lined up. To have correctly done so would have twist stressed that short hose... something to avoid for obvious reasons.
Very hard to spot unseen hose fatigue wear like that even by an observant car user who does lift the bonnet as all car user should do to check for pending problems. Losses of coolant at Motorway Speeds would be far more rapid because of higher coolant pressure with Motorway engine speeds. Hard to spot at engine idle speed. The previous owner obviously knew about coolant being lost but not where from. He had been topping up and when I checked the car the day I picked it up, the Coolant Expansion Bottle had been over filled to the top of the filler neck... leaving no air gap for expansion. The previous owner is a railway engineer so knows his way about a box of tools. Less so about what goes on under a car's bonnet.
There's always a reason for these things... always.