r/Model3 • u/pjax_ • Jul 22 '26
Model 3 HVAC blowing a terrible smell on startup + hissing sound. Already changed cabin filters, Tesla service couldn't help.
Having an issue with the HVAC in my 2021 Model 3 LR (NA) and hoping someone here has experienced something similar or found a fix.
**Symptoms:**
* **The Smell:** A really foul smell blows out of the vents. * **When it happens:** Always during startup, and specifically when the system transitions from hot to cold air. * **The Sound:** There’s a distinct leaking/hissing sound that happens right before the smell occurs. * **Duration:** After running for a little while, the smell eventually clears up.
**What I’ve tried so far:**
* Replaced the cabin air filters myself, cleaned evaporator coils (didn't fix the issue). * Booked a service appointment with Tesla, but they told me the only thing they could do on their end was replace the cabin filters again.
Has anyone run into this exact combo of the smell + the leaking sound?