Not sure but I think the thermostat housing is cracked. Car has 39000 miles. I am the original owner. Is this a common issue? Anybody replaced theirs if so. Where is it located and how difficult replacing it.\n\nWhy do you think the thermostat housing is cracked without knowing where it is?\n\nI'd do a really good inspection of the entire engine bay and I'd start passenger side about where the water pump is for starters.\n\nIf you have a black light that helps a ton to find coolant.