Sweet Smell from AC
A sweet smell when the AC is on typically indicates a coolant leak from the heater core, as the sweet odor is characteristic of ethylene glycol-based antifreeze. The AC system can draw in the smell from the heater core area.
Diagnosis Details
Possible Causes
Leaking heater core – Coolant leaks into the cabin, producing a sweet smell when the HVAC system is running.
Coolant leak from hoses or connections near the firewall – Leaking coolant can be drawn into the AC intake.
Contaminated cabin air filter or evaporator – Mold or mildew can sometimes produce a sweet or musty odor, but this is less common.
Related OBD-II Codes
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What You Should Do
Check coolant level and inspect for leaks under the dashboard (passenger side) or near the heater core.
Look for dampness or sweet-smelling residue.
If the heater core is leaking, it will need replacement.
Also inspect hoses and the radiator cap.
A pressure test can confirm the leak.
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.
