1998 Lincoln Mark VIII Q&A
1998 Lincoln Mark VIII Question: What causes the heater not to blow hot on my 98 mark viii? It only blows cold.
If the coolant is full, and the heater core is hot at operating temperature, then you possibly have a temp/actuator bad. - ProfessorG
In my experience, the blend door actuator is broken. When you activate your heater, the blend door rotates to direct the air through the heat exchanger to warm/heat the air. There are plenty of instructions online for do-it-yourselfers. If you have it done by a shop, it will be expensive, the parts are cheap, but it is labor intensive. - jpaul