Coolant Loss

[kngpen]

I also have this same exact problem. Tested with good results (no leaks or anything) My radiator was replaced at about 95k miles and its had the slow loss ever since. I just fill it up with water whenever it is thirsty

[George Davis]

I suggest a cylinder leak-down test. Coolant disappeared from my chevy truck in much the same way. No smoke, no driveability problems, no leaks. It was a head gasket leak, allowed coolant to be sucked into one cylinder and blown out.

[chamilun]

if you are losing the coolant, but only the amount that would normally be in the expansion tank, the problem is your expansion tank.

whats happening is when the system builds pressure/heat, the small impossible to see cracks will leak. cold pressure test will NOT identify these leaks. if your expansion tank is older, buy one (around $50) and replace.