lester ... 12/26/2012
2000 Mercury Grand Marquis LS 8 Cyl 4.6L
Body & Interior
1988 Lincoln,the heater heats on and off
The heater heats a while and how cold
Several possibilities; incorrect coolant mixture (not at 50/50 anti-freeze and water mixture), faulty heater control valve, faulty / clogged heater core, faulty / clogged heater hoses, faulty heater blower motor, faulty blower relay or fuse.