Q&A

 Master

You may have a heater core that is beginning to leak on your 98 Expedition. The cooling system should be pressure tested to try and determine the cause of any coolant leaks. Special attention should be paid to the heater core area, behind the dash on the passenger side.

 Master

Russ is correct. More importantly if you smell coolant, you have to check your coolant level. The last thing you want is to overheat the engine.