Interesting coolant leak.

[tacticalturnip]

you may want to wiggle the fan blade when engine is cool while looking at the shaft of the water pump & the weep hole and see if the leak is coming from there. Im pretty sure if it was the hose it would leak while running and not just when engine is off. theres pressure on the hose after running for a while the leaks can look like they come from a area when their not.

I'll give that a good look as well. Not something I would have considered.

 

[Too many Kubotas]

I had the same cold-only leak going with my CK2620.

Did what Hay Dude suggested earlier and added a second clamp. Done.

 

[Rovcketman357]

Have a mystery leak on my L3600. Only happens at certain times of the year i.e. certain ambient temps I suppose. Cannot find any evidence where it is coming from. I will try adding a send clap on the lower hose at the engine. I did check that factory clamp an it is tight. Never is much just enough to drop the level in the recovery tank. Would be nice to add a fluorescent dye to the coolant and check with black light.

 

[Too many Kubotas]

Pressure test the system?

 

[Rovcketman357]

Pressure test the system?

Don't have a pressure tester.

 

[tacticalturnip]

I had the same cold-only leak going with my CK2620.

Did what Hay Dude suggested earlier and added a second clamp. Done.

Picked up another hose clamp on the way home from work. Better to just tighten the old one and add a second, overkill seems like a plan here.

 

[flyerdan]

Being the lower hose, it's suction and at negative pressure to atmosphere so it wouldn't leak under power. Chances are it's a small rust or, as mentioned above, crystals from the coolant that allows a small bit of seepage. A second clamp may solve it depending on where it originates from; if not it will have to come off and be cleaned with a wire brush and the inside of the hose cleaned as well. A small bit of white grease will keep it from reoccurring.
If you don't want to take the hose off, you might be able to loosen the clamp and twist the hose a bit back and forth to break up the channel that's allowing the seepage, but that could make it worse as well.