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Q: Death in the A/C

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A few days ago I turned my car on and there was a loud rattling sound in the engine for a while. It eventually stopped but the next day when i turned it on, there was a death-like smell coming out of the air vents. Once I realized the smell and sound was coming from the vents I turned it off. The smell is only evident when the ac is on. I am sure it's something worse than regular grime or mildew, and I would like to figure out how to solve this issue and if possible do it myself.
My car has an automatic transmission.

A: Hello, thanks for writing in about your Aud...

Hello, thanks for writing in about your Audi A6 Quattro. You should remove the A/C blower motor and see if a mouse or rat got into the A/C system if the smell is as bad as you're describing. They can sometimes get into the system and they are killed by the blower motor. If this happens there's usually a loud noise followed by a smell. If you need help with this, consider YourMechanic, as a certified technician can come to your home or office to diagnose the smell for an accurate fix.

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