Alright well this is the third time ive smelled it. Driving home tonight i smelt a few wiffs of what appears to be coolant. Now i smelled the air coming out of the vents i dunno if it smelled any different(i think it did but it might just me thinking it does). Felt around the carpet areas by firewall no signs of anything. I have been working with coolant and it might be on my seat/coat/carpet who knows from when i was working on my girls car and i maybe smelling that i dont know! So how can i know for sure if its the heater core or not?

 

If you don't see any coolant under the car or on the interior floor, then it's probably ok. The leaking coolant would have to go somewhere, like when the core on a pickup i owned was leaking, the carpet was always wet.

If you're still not sure, try pressure testing the cooling system. You'll see the leaks then!