Greetings,

The other day I drove about 200 miles on the highway, and after pulling over to fill up I noticed a smog smell coming through the vents while the ac is on. I can only smell the smog when the ac is on. Car isn't acting out of the ordinary, mpg is all normal. At first I thought I had just gotten bad fuel. Since I smelled it for the first time immediately after leaving the gas station. Driving another 200 miles back home, I filled up again at another gas station and the issue has still been taking place. Last month I had a complete tune up and oil change performed. Had the air filter, all spark plugs, and the intake manifold gasket replaced. The car has been running really smoothly. Passed smog a couple of weeks ago and got my certificate. Still runs smooth, just smog smell from vents while using AC. No engine error codes using scanner, or notification lights whatsoever. Holds oil, and coolant levels steady with no leaks. Any advice on what could be going on would be greatly appreciated.

Thank you for your time.

 

When was the last time you changed your cabin air filter?
Your cabin air filter filters the air before it comes into the cabin of the vehicle. Just like a furnace filter does in your house.

If you drive long enough without changing it, it accumulates a combination of all kinds of different smells which are the sum of everything that has gone through it or tried to go through it but can't because it's clogged up. You can end up with mold and mildew among other things.

Things also grow on the evaporator coils which is The part of the system that cools and dehumidifies the air.

You can buy AC system cleaner in a spray can with one of those red tubes that lets you focus the spray very tightly.

I would change both of the cabin air filter and clean off the evaporator coils. Follow the directions on the can.

 

Thank you for the suggestions derf. It has been a couple of years since I changed the cabin filter. I picked one up at Autozone for about $20 earlier this afternoon. I'm going to swap it out tomorrow, and see if that makes a difference. Thank you again.