l have a 1989 Grand Marquis. The car runs great it has one slight coolant leak where the lower radiator hose joins with the radiator. l only ad like 1-2 cups of coolant per month. l do not smell any coolant in the exhaust. When l floor the car l can smell antifreeze really bad in the car.l think l only smell it when my heater is on. l do not smell it any other time and ive checked my passenger side floor and against the firewall and l do not see where the heater core would be leaking from if it were. Im just at a loss.

It maybe just ne a small leak but if you can smell it inside the car then get it fixed right now, the smell maybe sweet but its bad stuff ! I've seen leaks that run under the padding/sealeat at the firewall and you could only smell it but not see it.

Anyways its bad stuff so get it fixed ASAP !

Leaking Heater Core.. How to test system, Pressurize the system , look & listen for leaks. Even if you find none the system probably will not hold pressure for very long. If so, bypass the heater core, pressure test radiator again. If radiator is holding pressure, then you know for sure your heater core is bad. But fix that Radiator leak first.