R107 coolant mystery leak
 

Coolant empty, but no known leak spot.

Seems to only leak when the car is resting or cool. Seems to hold the coolant while I'm driving it.

I'm in the process of replacing the hoses, but that choice was made based on the age, I don't see any fluid on the hoses.

Your suggestions are appreciated.

I have not crawled under the car yet. The garage floor is just sopping wet.

Slithering on the floor is in my future, but your guidance on where to look is appreciated.

Radiator - newer
 

and there's no coolant under the radiator, which is about 10K miles old

Possible leaks may be coming from an expansion (freeze) plug or the water pump weep hole at the bottom of the water pump. Try to isolate whether the liquid is coming from the front, middle or rear of the engine. By doing this you may be able to identify closer where the leak is coming from.

most likely water pump. had many of them leak during cooldown. i pressurize the system and let it sit overnight. good luck, chuck.

not a rotten radiator trans line? had that before,pink trans fluid

Do a cylinder leak down with the rad cap off and look for coolant to rise / bubbles. If it does, there is a combustion to coolant leak.

Also pressurize the cooling system to 15 PSI and look for leaks.

Have a look at the AC condensate drains, on some cars if the heater core is leaking it will come out of the drains.

Got the parts
 

Thanks.
I have the water pump and the hoses, hope it fixes all

I will advise my success after I complete - in several weeks