I know this has been asked about a thousand times--I have a coolant leak, and I can't figure out where it's coming from. I'm trying to figure out if there's a place that poses a higher failure rate than others. I'm not sure I can afford a complete cooling system overhaul at the moment, though I probably need one. Car has 144k miles.

Anyways, here's what happens--Coolant will leak out over the course of about 2 days of driving, but it will only fall to a certain level. At this level, the car runs fine and the temp needle remains centered. The only indication I get is the low coolant light cycles on and off. It'll be on for about 5 mins, then off for 30. Something like that. If I take the cap off the expansion tank, it's dry. I fill to the proper level, bleed the system, and it's good for 2 more days.

I cannot for the life of me find where the leak is coming from. Under the car looking up, and looking under the hood, I can see nothing.

The car has a new OEM lower radiator hose, and a slightly dubious used radiator from a Ci. (rolls eyes) I've replaced the expansion tank like 3 times over the 3 years I've had it.

My question is, after the expansion tank, is there another likely failure spot that I could start with replacing?