The curious case of the air leak and bad efficiency
So I have got a 2023 Ioniq 5 Limited RWD and I have been dealing with the strangest issue. Basically, the moment I touch any HVAC control — even just bumping the fan on for a second and turning it right back off — outside air starts pouring into the cabin and my efficiency tanks by roughly 30%. Hoping someone here has run into something similar.
TL;DR: Any HVAC interaction (or the car's "smart ventilation" doing its thing) seems to cause ram air to flood the cabin, and efficiency drops from ~5.2 to ~3.8 mi/kWh city, and ~4.2 down to ~2.6 mi/kWh highway (75 mph, cruise, warm San Diego weather, HVAC fully off). It is not Active Air Flaps issue.
When everything is good, no air leaking in, I average 5.0–5.2 mi/kWh. Once it triggers, outside air rushes into the cabin. You can tell it's ram air because the faster I drive, the stronger the airflow — it scales directly with speed. Hitting recirculate doesn't fix the issue either, it just redirects the air leak down to the footwell. Efficiency improves a tiny bit on recirc, but nothing close to normal.
On my usual work commute (city roads <30mph, warm weather, same driving style), efficiency drops to about 3.8 mi/kWh. On the highway at 75 mph (using cruise control), around 2.6 mi/kWh. This is with the HVAC completely off.
I have stumbled onto two oddly specific ways to reset things and get the air to stop leaking in and to reset the efficiency again
- Charge the car — Plug into L1/L2 charger, let it finish (or stop via Bluelink) charge for atleast 1hr. The front vents flaps are in the open position during charging, and they close once the charge is completed or stopped. This cycling of the vents somehow seems to fix the issue. This is the most reliable method to get back to high(normal) efficiency. And as soon as I touch the HVAC again or the smart ventilation kicks in, the issue is back.
- Remote Smart Parking Assist — If the car has been sitting for a couple hours, using the fob to pull it out of the spot seems to cycle the front vents and reset everything. Doesn't work if you try it right after parking though — the car needs to have been resting. Works most of the time, not always.
Any idea what might be going on here?
PS: I took it to the dealership and they are trying to write it off as "normal", they throw the same cliche that "efficiency is variable" and "it depends on the conditions" without actually addressing the core issue. Also on the air leak, they claim to have tested on other Ioniq 5s and all of them had the the air leaking-in so "there is nothing to fix". ..... is this true?
They kept my car in for 5 days and I have been monitoring the activity of the car and they haven't even attempted to replicate the issue. They just seem to be dismissing it without proper investigation.