Tonight I popped out in my partners car and noticed an awful burning/chemical smell whilst driving, this smell got worse if you turned on the AC (FAN BLOWER), so I got her to pull over and had her pop hood, nothing stood out from the unusual but I could detect that the smell was coming around where the battery lies, however I didn't want to sniff too much as I don't know if its toxic, the smell might be coming from under the battery I don't know, but definitly is stronger than anywhere else.

The smell is present while driving and for 10mins after the car engine has been turned off, its awful, rubber and chemically smell.

Sadly due to the Christmas period I'm unable to take her rather old car (Nissan Micra 2000) to my local garage. She has just had a MOT and had some wielding done under neath the car but that was over a week ago and it worked fine up to now, shes due a new car in the new year and I'm hoping she can make do for a couple of more months.

Attached is a image where the smell (red circle is where I think is coming from):

car design

From what I've read online it could be a indication that the battery is going faulty, but the unusual thing is that it doesn't smell like rotten eggs as so many people describe. I'm hoping the weather is better tomorrow so I can take a better look but wondering if any wise sparks can give me a better indication what it could be....


  • Smells of Rubber / Chemicals
  • Comes from passenger side near battery/fuse box area
  • Does not smell of sulphur (rotten eggs)
  • Does not smoke or at least visible smoke
  • Downfall of rain today was heaviest its been in decades

1 Answer 1


As far as chemicals in that area you have coolant, which does not typically smell even when burnt, but check the level anyway, and your brake fluid which can smell quite strong when burnt. So check those two levels. Rain can wash oils and fluids off cooler parts of the engine compartment onto hotter ones causing them to burn.

You can test the battery with a multi-meter. It should read around 12.5 - 13 Volts when off and 13-13.5 when running. If its over when running the regulator/alternator is bad and your likely smelling it or wires burning. This usually fails totally pretty quickly though. A burning/venting battery will have a metallic smell and usually burns your nose. (Not severally but irritating and unhealthy all the same.)

Thats the few things off the top of my head to start checking based on the location and weather conditions.

  • Coolant usually has a distinctly sweet smell to it, though wouldn't make a difference if burnt or not. I do agree with your suggestion of checking the different levels, though. Dec 31, 2015 at 7:57
  • Hey @JpaytonWPD just got back from testing the voltage on the battery, the voltage is 12.53v off, and 14.34v on... so looks like the alternator? car still running ok mind. Dec 31, 2015 at 14:36
  • @SimonHayter Those voltages look fine.
    – HandyHowie
    Dec 31, 2015 at 14:47
  • 14.34 is a bit high for anything here in the US. Not super high but may be worth a test. Many auto part stores will test the alternator if your remove it and take it to them. Are you still smelling anything after the rain? If its dirty inside the engine compartment some foaming engine cleaner could help also.
    – JpaytonWPD
    Dec 31, 2015 at 19:49

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