2001 mercury grand marquis 140,000 miles. Small amount of steam from between hood and windshield, strong coolant smell after driving 4 hrs on trip out of town. Temp gauge normal. Engine running ok. No leaks underneath. Drove another 4 hours same situation. Drove short distance next day (2miles) no problems. Day after that will not start & 2days later coolant on driveway. No coolant on floorboard, thought might be heater core.