[EngineerTheVoid]

I have noticed a very bad smell from the AC when starting the car and is so bad I need to open the window. After running the AC for a bit the smell gets better. It happens after the car has been sitting for just a couple of hours. Noticed the smell this past week.

Has anyone experienced this issue before? My car is garage kept, I wonder if some animal has gotten into the AC vent or if this is a moisture/mildew issue. I have 5k miles on the car.

[ednir98]

What does it smell like? I've noticed the first couple seconds of AC in my X5 always smells weird but it shouldn't last more than a few seconds.

[EngineerTheVoid]

Originally Posted by ednir98

What does it smell like? I've noticed the first couple seconds of AC in my X5 always smells weird but it shouldn't last more than a few seconds.

The smell is musty, so much so its too strong to keep the windows up. It lasts for a couple of minutes. It began about a week ago. I didnt drive the car for a few days. Then yesterday it smelled when leaving my garage in the morning and again after being parked outside for 3 hours.

[ednir98]

That's odd. Have you checked around your external vents for leaves and debris? Definitely worth checking your cabin air filter as well, should be under the passenger side dashboard if I'm not mistaken. Could have some leaves or other junk in there decomposing.

[KC87ZB]

Originally Posted by M2siast

You must have a dead animal in your car...

I was thinking something died in the intake path to the HVAC if it is that strong. The other concern would be an evaporator drain that is fully plugged so you have stagnant water but that usually presents as water in the footwell more so than a smell (water first and smell later). Thus check both footwells and ensure the carpet is not wet.

Those are the very easy things to check.

[EngineerTheVoid]

Thanks everyone for the input.

I was able to fix this issue by running the heater full blast for 5-10 min. I guess there was some moisture inside the vents that this dried out. Its been fine for the past few days now.