This car is a 1996 Civic. It has steam coming from the vents with the smell of coolant. The heater core is new, so it doesn't seem likely that the heater core is bad. Anyone have any ideas?

 

you could always rent a pressure tester for a local parts store ....if the pressure drops .....you got a leak!

 

it could be a rebuilt or new leaking heater core. or residual burning off. Also check you coolant level each day and see if it is going down,.

 

my old acura did that rite after the head gaskit blew.

 

The heater core could be bad. Its not that uncommon to get a bad part new. But like a previous poster said, it could be coolant left over from the leaking core. Keep a check on the coolant level and drive it for a few days. A lot of times after doing a job, a small thing thing like tgis will pop up and it will spook you. Lol

 

Not uncommon to buy defective new parts,see if the problem goes away after a few days.