Have you tried switching the ventilation to recirculation mode and then turning on the fan? If the problem doesn't change it probably means the issue is in the interior of the car not exhaust gas being drawn into the cabin from underhood.

Exhaust gas contains carbon monoxide which is colourless and odorless. If it was getting inside the cabin, if anything, it would probably make you feel drowsy.

 

I turn off fan to drive and open the window some times, it is ok.
Actually I fear to turn on the fan to drive after got serious sick twice.
I did not try recirculation mode and turn on the fan yet, maybe I need to have a try.
Thanks a lot.

 

Just another thought, do you use the whindshield washer regularly? Is it possible that you have something other than squirter fluid in the jug, or a fluid that you have a sensitivity to?

 

Actually I seldom use windshield washer.
Anybody know any reason the breathing difficulty problem is much worse in sunny day time than night time.
I really wonder it is because of allergy, or emission leak, or some other issues.

Thanks a lot.

 

One other thing you could try is to swap cars with a good friend for a few days. If they drive your car the same way you do and have no health issues, then the problem is going to be something strange and unique only to you.

 

Maybe you have an allergy or reaction to the off-gassing that happens to the interior plastics and adhesives. That might explain why it is worse on a sunny day than at night since the heat and sunlight probably accelerate the process.

If that is the case it will probably get better over time as the "new car" smell disappears.

 

Actually it is a used 2008 sonata, and I got the breathing difficulty problem one month after I bought it .
And the dealer also did a drive test trip for almost 100 miles in night time. they do not have the same problem as mine. Dealer said there should be noise to be heard if some leak exist, but can not hear any noise.
Do you have any idea if it is because of the interior plastics and adhesives ? But why I do not have the problem in the first month ?
Something bad accumulated and trigger my breathing problem ?

Thanks a lot.

 

I had a winshield replaced once, in a '68 Charger, and I recognized "engine smell" right away, and to show the installer that I wasn't making this up, I put a sheet of paper on the dash, and it slid into the engine compartment!

 

Can anybody have some document or figures to describe the whole vent system for the air flow in all mode ?

Thanks a lot

 

You can view the entire Hyundai factory service manual (FSM) on line at
http://www.hmaservice.com/
Sign up, it it free and it is direct from the manufacturer.