Heater Core Replacement (Dash-Out Job)
Eight-to-twelve-hour dash-out job. Heater core under the passenger HVAC box. Mopar 4720001 / Spectra 99317. Don't skip new heater hoses while you're in there.
Heater core replacement is the worst regular service job on the XJ. The core sits inside the HVAC box on the passenger side under the dash, and Chrysler did not design it for service - the entire dashboard must come out. Plan a full Saturday. Symptoms of failure: sweet coolant smell in the cabin, foggy windshield that won't clear, wet passenger carpet, coolant level dropping with no external leak. Buy quality - Mopar 4720001 or Spectra 99317, NOT the no-name aluminum cores which leak again within months. The job: drain coolant, pull center console, knee bolster, instrument cluster bezel, instrument cluster, radio, glove box, lower dash trims, then the steering column drop, then the four dash bolts to lift out the whole dash assembly. Heater box pulls free with three bolts. Replace heater hoses and the cabin air mode actuator (blend door, see separate entry) while you have access. Reassembly reverses; expect to find spare bolts you can't account for - that is normal.
Why it works
- Restores cabin heat
- Stops coolant smell
Trade-offs
- Hardest routine job on XJ
Tools required
- full socket set
- torx set
- trim pry
- FSM
- patience
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Heater core Mopar | Mopar | ~$100 |
| Heater hoses | Gates/RockAuto | ~$25 |
| Blend door actuator | Dorman | ~$30 |
Sources
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Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.