I just purchased a 99 Accord from an auction, the car runs good and all, but it reeks of antifreeze after the car warms up.

Things I've noticed:
The heat doesn't blow hot, just mildly warm
If I turn the heat down to cold instead of hot, the smell stops
There is no condensation in the vehicle
The floor/carpet is completely dry
I haven't yet detected any drop in coolant level

I keep thinking heater core, but it doesn't make sense to have a heater core leak without any dampness or condensation... please help!!! I'd hate to go through the trouble (and cost!) of replacing the core only to find out it was something else...

Thanks!

 

Use a cooling system pressure checker and see if it holds pressure over time. You may have something leaking on the engine which would give you the smell but turning the water valve off and the smell going away would suggest something upstream of it which is heater hoses and the heater core.

 

That being said, doesn't a heater core leak always result in condensation and/or a wet floor board?

Are Accords common for heater core problems?

Given the heater core setup, if there were a leak at the hose where it connects to the heater core, could that cause a smell in the interior?

 

If you don’t have the heater on recirculating air you may get the smell in cabin. I have a 95 Accord and just the little fluid leaked from opening the radiator cap brings the smell into the cabin. From reading post on here leaking heater cores are not common.

“That being said, doesn't a heater core leak always result in condensation and/or a wet floor board?”

Not always as a small leak will give you the smell but not enough to leak on the floor or fog up the windows. I think the location of the leak on the core will matter also. I think the best thing to do is pressures check the cooling system and locate the leak. At some point most companies went to plastic tanks with a gasket between the core and tank and these will leak at some point. I don’t know what Honda used in your vehicle.