Coolant leaking visibly into the passenger compartment is a sign of a faulty core or core seal. A sweet, anti-freeze odor in the car's interior or a constantly fogged windshield may also indicate a faulty core. Inspect the carpet and the area near the floor vents for any signs of moisture or coolant. A leaking heater core may be caused by over pressurization of the cooling system. 

To replace heater core: 

  1. Drain the coolant as described in the cooling system.
  2. Remove the instrument panel.
  3. Remove the two hose clamps and hoses from the heater core. They are accessible from inside the engine compartment. Plug the core openings to prevent coolant from spilling.
  4. Remove the air distributor by removing the toe nuts that hold it to the heater box. Separate the distributor from the left and right air ducts.
  5. Heater hose clamps and hose to be removed from heater core. Removed clips by squeezing tangs.
  6. Remove the heater box and control cable assembly by removing the three nuts that hold the box to the car and by disconnecting the defroster duct and the fresh air blower housing. Discard the old soft seal.

WARNING: While our customers have found this information useful, these articles/links are not from technical publications.  Information presented here is to give you a general idea of what to do and how to do it. Auto repair, while fun and economical, can be dangerous.  There is no way we can warn you of each and every hazard.  How can we tell you that when installing a hub cap, don’t smoke and have a bucket of gas nearby?  If you have no common sense, ignore these articles.  Otherwise, read the warnings in the front of the Robert Bentley manual before you proceeded to follow any advice given here.