I have a 2010 Subaru Outback that I bought second hand. The first few weeks it was fine, but then suddenly a bunch of lights were flashing on the dash.

So I replaced the thermostat and did a full coolant flush. A few weeks later, the coolant levels were low again and I realized there was a leak coming from the bottom of the radiator. A few drops per hour.

I tried to use radiator leak stop to no avail.

Then I tried to patch up the bottom of the radiator using metallic paste

But it still drips. It’s not an urgent issue, the car runs fine and I top off the coolant once a month. But it’s annoying and the car always smell like coolant.

Any ideas on a fix? How hard/expensive would a full radiator swap be?