Car guys on a local radio station suspect a head gasket.
Mercury Q&AAsk Your Question
2004 Mercury Marauder Question: Heater blows cool air at low rpm.
Answer #1Stan's Garage (109 Answers) , Dearborn Heights, MI - (313) 915-4196Stans Garage January 22, 2011, 15:30Technician
The first thing I would check is the coolant level. It could just be low. Other causes could be a restricted heater core, low pressure from a worn water pump. The head gasket should be the last thing to check. If you want us to check this out just call and schedule an appointment (313-562-7022). I am sure we can diagnose it and give you the answer you need.
Answer #2DaveJHM January 23, 2011, 01:03Master
Agreed that the head gasket is a low percentage chance for failure on this engine...