Strange water leak??

[rumpelstiltskin]

Just fired up my little 5 turbo for the first time in months as ive been restoring it.First radiator that was in the car leaked like a sieve!,had a really good spare and stuck it on.I've never had this before but the car doesn't leak when idling for ages(was testing to see fan kicked in),not a drop.Leave it that day and nothing on the ground,next morning quite a few drops of coolant on the deck???Seems to be falling from bottom of the radiator on the fan thermostat side but i can't see where it's coming from?Anyone had anything similar?Surely when all the pipes are red hot and at full pressure it would leak then,not when cool?

[s3irios]

Well when it cools off the metal actually shrinks a bit so any possible cracks or leaks will leak. The water pressure building up will show the leaks in cooldown.
Another thing is that when engine running water's runnign through the system too. When it cools off the excess pressure that builds cause of the thermostat closing will cause the leak to show.

[Adam 005]

I would remove rad and have i presure tested to rule out any problems(secound hand rads can play up after sitting around along time). If that comes back fine then spend some time checking coolent hoses for damage and replace any hose clips that are old and or out of shape.
When refitting rad remember not to over tighten the hose clips as this can lead to coolent leaks.

Do not drive the car until cooling system is 100%. An over heating GT is a dead GT