Losing Anti-freeze on 1995 Mercury Mystique

I have been losing a quart of antifreeze every about every 140 miles. It's got worse over time. 2 different shops say they can't find a problem. They've replaced the thermostat and gasket, done a pressure check and checked the exhaust gases and found no problems. After the car is warmed up, there is a heavy smell of anti-freeze coming from the engine compartment but no visible signs of leaking. Any ideas? Thanks.

Asked by for the 1995 Mercury Mystique
Sometimes the heater core will have a slight leak and it will usually drip down the inside of the firewall on the passenger side, Feel around the carpet area on the passenger side below the glove box. Maybe they pressure tested it with the heater off.
Have you changed your radiator cap, They become weak over time and maybe releasing fluid out of the overflow tank. Your vehicle calls for a 18 psi radiator cap, The cap is a pressure relief valve for your cooling system and if it becomes weak it will release coolant when hot. Remember never open your cap when the engine is hot.
Thanks for your help and suggestions. I unfortunately have bad news. I needed to see if I could get it fixed, so the shop I took it too thought it was the water pump as they could see anti-freeze from that area. Well when the tore into it, they found the head gasket leaking. So, with the mounting repair costs, I have decided to get rid of the car and find something else. Thank you for responding.
3 more answers
Sounds like a head gasket my friend.
Replace the whole thermostat housing. There is a plastic lip that holds the gasket to in place that crumbles when replacing the housing to block gasket.
These cars are complete junk! I had to have my head gasket replaced as well!