2002 mercury sable overheating

Let's go over a list of things here and get everything organized. Most cars have an "open" coolant system, meaning that if it gets too hot (thus increasing the pressure inside the coolant system), the reservoir or radiator cap will open up and allow that pressure to release, or the coolant to expel - which would cause you to spill coolant.

After it cooled down, you were able to drive it for 70 miles - presumably on the highway/interstate/freeway, or another road that may not have a whole lot of stopping.

Then you started driving in town, most likely with stoplights or stop signs. The car overheated then and you weren't able to get it restarted (which is normal and is a safety feature on a lot of cars).

Fluids are good, the fan is kicking on, and the belts haven't broken.

Okay, so you actually did a pretty good job narrowing this down (assuming I didn't miss anything). The car is doing it's overheating when you're in stop and go traffic, with low airflow. If you are running your air conditioning, try turning it off and see if that keeps you from overheating (assuming the car starts now). If it does, then chances are your fan isn't kicking into high-speed. On some vehicles, you have two fans, on others you only have one. If you have two fans, one will only kick on when the AC is running. If you have one fan, it should have two speeds. A low-speed for simply cooling the engine, and a high-speed for when the AC is running.

If you don't overheat when the AC is running, check your relay box under the hood and search for a relay that should be labeled something along the lines of "Fan 2", "Fan High", "Fan AUX", or "Fan AC". If you find one, replace it or try switching it with another relay. Good luck!

I had the same issue on my 2002 mercusy sable LS a couple monts back. Had to replace the who fuel system. Not cheap since its in the gas tank. cost about 600.00 bucks. We tried to replace the filter first and the smell stopped for a week then came back and then we relpaced the more expensive part. Still love my car I only have 72000K

The overheating could be a stuck thermostat, or a failed water pump among other things. If you are loosing coolant faster than the leak on the hose, you may be burning it out the exhaust pipe. Which would point to engine problems.
If the temp gauge is not showing the engine is hot, and the fan is not coming on, what you are smelling may only be the drip blowing onto the exhaust pipe. The engine may not be running hot.
A mechanic would use an infered thermometer or a scanner to "read" the engine temp to verify it is overheating.
There is a chance the system is not actually full and has air pockets in it which would need to be bled out.

Check your coolant level visually by removing the radiator cap (only when it is cold). Also make sure the coolant temperature sensor for the cooling fan is functioning properly. These are set to operate the fan when the engine coolant reaches a predetermined temperature. These go bad in time and need replacing. Sounds as though yours may be working intermittently.

First replace your Thermostat, and then have your Electric cooling fan checked.

Try getting a scan at Autozone, Advance, or Oreillys autoparts. They will do it for free. Or if you just want to buy a few parts, observe if the cooling fan even comes on. There are 2 temperature sensors on most Ford's and one makes the dash gauge work and the other makes the Electric cooling fan work. Just have the car a little warm and when you get the dash gauge to move, disconnect the temp sensors one at a time until you find the one that controls the gauge. The remaining sensor controls the cooling fan. Remember, the gauges only work when the engine is running.

If your cooling fan still does not work, ask the parts guys how many speeds your vehicle is suppose to have on its fan. Usually, when the A/C is turned on, high speed kicks in; for sure when you have overheating, it should be on high speed. The Electric cooling fan has a Relay that can be bad. The fan motor can also be bad.

The loss of Antifreeze in the system can be from boil over. As long as the car runs decent, there is no reason to expect a blown head gasket. With the Radiator cap off, you may be able to see bubbles on the surface of the radiator if a head gasket is allowing compression to get into the cooling system.

Just start with the easiest things like a Thermostat, then go to the next solution and work your way through the possibilities. I hope my comments are useful to you.

sorry to say u need a heater core and the system flushed

Check the thermostat. The temperature sender is to the right of the thermostat and if the thermostat doesn't open the hot coolant from the block won't be flowing to the sender/gauge showing it is overheating. The thermostat is at the end of the top radiator hose where it enters the engine. Check the wires to the sender to make sure they are connected. Flush the coolant and heater core at the firewall connections as it may become clogged.

The thermostat may be wearing out. A thermostat controls the engine temperature to keep it at a consistent temperature, The other fan will probably turn on if you turn on your Air Conditioner.

the indicator in the dash is faulty

sounds like heater core.If not to bad yet right floor board won`t be wet if bad enough right floor below heater will be wet.Turn defrosters on hi windshield moisture probly heater core