Coolant loss after radiator replacement

[streetwaves]

Hey guys. I recently had my car in the shop, and among other things they found a small leak in the radiator. They thought it could get bigger at any time so they replaced it. A couple days later I noticed that while cold and on a level surface, the level of the expansion tank was an inch or two below the 'kalt' line. In the next few days it kept creeping down lower and lower. So I filled it up to the line with coolant and the same has been repeating. I filled it up to the line last Friday (a week and a couple days ago) and it's already a couple of inches at least below the line. Any ideas?

The car does not run badly at all, I don't see coolant in the oil, and nothing leaks on the driveway other than power steering (small leak).

[Jaxx_]

Hey guys. I recently had my car in the shop, and among other things they found a small leak in the radiator. They thought it could get bigger at any time so they replaced it. A couple days later I noticed that while cold and on a level surface, the level of the expansion tank was an inch or two below the 'kalt' line. In the next few days it kept creeping down lower and lower. So I filled it up to the line with coolant and the same has been repeating. I filled it up to the line last Friday (a week and a couple days ago) and it's already a couple of inches at least below the line. Any ideas?

The car does not run badly at all, I don't see coolant in the oil, and nothing leaks on the driveway other than power steering (small leak).

it could be bleeding itself. if it continues to do this for a long time (1 month+), might want to think about looking at your head gasket, hoses, banjo fittings, etc.

throw a clean piece of cardboard under the engine bay after you've come home. pull it out on the morning and see if there's coolant (this test will also check for oil leaks... :P ) on the cardboard. might be good to smell it as well, just to be sure it's not condensation from your A/C or anything. I wouldn't recommend tasting it, though. I know you said it's not leaking, but this is a test just to be sure.