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Q: Smell coming from A/C vents

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There is an odor in my car that comes in through the vents of the A/C system. There has been a leaking radiator, but it was replaced. That ‘had’ been a source of one odor, but now there is a 2nd one and it is literally giving me headaches. At times, the smell is rather metallic and like hot exhaust fumes. Yet, it also smells like hot fluid similar to power steering fluid or antifreeze. The dealer did a pressure-check on the cooling system and reported to me that it is not a heater core leak. I replaced the fresh air filters. Around the filters, I thought there was a gap and leak, but they appeared fine. The smell is only from the driver’s side a/c vents. When the airflow is on low, the smell is more pronounced. I crack the window or open the sunroof. I had also thought that it might be the exhaust back-drafting into the car. The dealer has not helped me one bit, despite the expense! Can you give me suggestions on the cause of this problem and how do I solve it?

A: Hello there, a few different items can caus...

Hello there, a few different items can cause this type of smell in the vehicle. The most common is the heater core, but that has already been checked. Other likely causes would be an exhaust leak, fuel leak, or something in the AC ducts. I'd suggest you get some help from a qualified technician, such as one from YourMechanic, who will be able to diagnose the smell you're experiencing and perform any repairs that are required.

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