Hard to say since recirculate up the fan speed too, and it seems to be more dependent on that...but your theory does make sense!Does it matter whether the A/C is set to recirculate? I'd imagine the problem is from air trying to escape, so if you are recirculating, the problem wouldn't happen because the air is recirculated instead of escaping?
Mine is starting to rattle some with the sunroof closed.
Anyone else experience this?
THIS surely is about TSB 161 (12/16) which follows my symptoms described as (Thank 2000UZJ for sending this to me):
With FAN SPEED HI I'm hearing a Flutter at the (seems like) Psngr AC Vent Area (Vs Sunroof area) that goes away WHEN THE WINDOW GOES DOWN OR Fan Speed down to Low.
It Started at first ONLY when the MODE was AC/DEFOG but Today I turned Off the AC (Fan Hi + RECIRC) and the Flutter remained.
Likely RECIRC is chosen (is for me) as it would seem an outside air source would not create as "Sealed a cabin" for the High Cabin Pressure to build .....
TSB 161 (Trunk) LUGGAGE SIDE TRIM REPLACEMENT
This bulletin provides the procedure to replace the luggage side trims on 2016MY Optima (JFa)
vehicles, produced from September 28, 2015 to August 16, 2016, which may experience a concern with high cabin pressure.
This concern is caused by the isolation pads of the luggage side trim assemblies blocking the extractor vents (I've actually felt my Ears Pop when I opened my mouth & didn't know why).
Follow the procedure outlined in this bulletin to replace the left and right luggage side trims.
Trunk Liner (LH) 85730 D5000WK
Trunk Liner (RH) 85740 D5000WK
Steps omitted but that's the gist of it. The sad part is they likely won't order the parts til they witness the issue, so I've been testing a lot to minimize wasted time at the Svc Ctr trying to prove this. MY issue is Not about the Sunroof BUT maybe the High Cabin Pressure issue affects MORE than one problem. FYI
Ask and you shall receive:
I do see that based on your avatar you appear to be from Canada, thus I'm guessing your car is a Canadian-spec Optima...in which case you do realize that these TSBs are applicable to U.S.-spec vehicles, no? For all I know there may be a Canadian equivalent to this particular TSB that your Canadian Kia dealer may be able to pull up but again I imagine Canadian Kia dealers may be under no obligation to recognize U.S.-sourced TSBs.