Finally ran the persistent coolant leak to ground on one of our family Tributes - would leak a cupful every 100Km on average so needed frequent topping up.

First thought I had it at the small hose under the water pump, replaced the hose itself and new hose clamps to replace the factory spring clamps. That solved that leak but within a couple of weeks it was leaking further back from above the tranny. Clearly another spring clamp had lost its tension and the problem just moved.

Dived in at the weekend, removed the thermostat housing and the water pump to head hose and replaced all the hose clamps with proper screw clamps and result! No leaks after a further 3 weeks.

The system wasn't over-pressuring, just the normal system pressure was overcoming the spring clamp tension, car is at 280,000Km and is a 2001 so its had plenty of heat/cool cycles for the spring clamps to lose their tension...

Not too bad a job to do but inevitably some of the ears on the factory clamps were hard to get pliers onto to compress them and remove...one in particular took around 30mins and a chunk of my right arm to get off :-) Took the usual 2-3 drive cycles to get all the air out of the system on refilling, Tributes/Escapes seem quite difficult to bleed the air out of.