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Question to all you car experts out there...

ideal.dreams

ideal.dreams

macrumors 68020
Original poster
Jul 19, 2010
2,386
1,299
I've been noticing a burning smell in my car lately. It's not constant, and it comes and goes when I stop quickly or when I accelerate quickly. I'm not sure if it's these two factors that's causing the smell or if it's just a coincidence, but I would like to know if anyone can shine some light on what the smell might be...

Thanks

Edit: After doing a lot of research online, I've found others experiencing the same problem. One person noticed the smell when the defroster was on, another noticed it after an air filter change. It's cold here in Ohio so I have the rear defogger on constantly and the front one on frequently. I also had my air filter changed a few weeks ago. Hope this new information can help a little :)
 
Last edited:
robbieduncan said:
Odd that it happens both braking and accelerating. Brake binding on?
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Like I said, I don't know if that's actually the cause or if it's just a coincidence. How can I tell if the brake binding is on? I'm completely lost when it comes to cars.

Edit: I'd also like to point out that the smell comes and goes when I have the climate control on, and also that I replaced my air filter a while ago.
 
ideal.dreams said:
Like I said, I don't know if that's actually the cause or if it's just a coincidence. How can I tell if the brake binding is on? I'm completely lost when it comes to cars.

Edit: I'd also like to point out that the smell comes and goes when I have the climate control on, and also that I replaced my air filter a while ago.
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You need to get down and look at the brake pads within the callipers (on both sides of the brake rotor). It's unlikely that you wouldn't notice it though: there'd be noise and quite possible you'd feel it. If it's coming via the air con system then I'd look into that first of all. Could a blower motor burning out?
 
ideal.dreams said:
I've been noticing a burning smell in my car lately. It's not constant, and it comes and goes when I stop quickly or when I accelerate quickly. I'm not sure if it's these two factors that's causing the smell or if it's just a coincidence, but I would like to know if anyone can shine some light on what the smell might be...

Thanks

Edit: After doing a lot of research online, I've found others experiencing the same problem. One person noticed the smell when the defroster was on, another noticed it after an air filter change. It's cold here in Ohio so I have the rear defogger on constantly and the front one on frequently. I also had my air filter changed a few weeks ago. Hope this new information can help a little :)
Click to expand...

What kind of car is it? Mileage, etc? If it has a lot of miles it could be passing oil out the breather of the valve cover when the engine shifts around while accelerating or slowing down hard, happens a lot in auto crossing. If that is the case its not really a big deal. But More info is needed before that conclusion is reached. Also what part of Ohio? I might know someone close to you that can check it out for you. We have a lot of Southern Ohio members on http://www.wvmotorsports.com.

When they changed your air filter, did they top off any fluids? They may have just spilled some and you are catching a whiff when your car warms up.

Once again all speculation without further info.

BTW rear defroster is purely electrical. If it was that there would be smoke in the rear deck.
 
gr8whtd0pe said:
What kind of car is it? Mileage, etc? If it has a lot of miles it could be passing oil out the breather of the valve cover when the engine shifts around while accelerating or slowing down hard, happens a lot in auto crossing. If that is the case its not really a big deal. But More info is needed before that conclusion is reached. Also what part of Ohio? I might know someone close to you that can check it out for you. We have a lot of Southern Ohio members on http://www.wvmotorsports.com.

When they changed your air filter, did they top off any fluids? They may have just spilled some and you are catching a whiff when your car warms up.

Once again all speculation without further info.

BTW rear defroster is purely electrical. If it was that there would be smoke in the rear deck.
Click to expand...

It's a 2003 Cadillac CTS. A little over 70,000 miles on it. I'm in Northern Ohio.
 
If it's electricity related (loading of the alternator / belt slippage) - turn on your headlights, crank up the blower, and turn on all your defrosters - if it shows up immediately that could be it.

Your AC unit may be on the fritz - most cars turn on the AC automatically when the front defogger is on (it dries out the air which helps defog your windshield faster)

When you accelerate rapidly - the air compressor on most newer vehicles automatically cuts out - to temporarily reduce the load on your engine.

Smelling it during acceleration and after stopping - it's possible the smell is there the whole time - but when you're accelerating hard you're likely coming from a slow speed / stop - so this odor that's there the whole time, builds up. (once you're driving - the air movement dilutes the odor)

Does this happen from a cold start - or does it have to be running for a period of time first?

What type of burning smell? Rubber? Oil? Fried electronics? Is it a sweet smell? Acrid?
 
Big-TDI-Guy said:
If it's electricity related (loading of the alternator / belt slippage) - turn on your headlights, crank up the blower, and turn on all your defrosters - if it shows up immediately that could be it.

Your AC unit may be on the fritz - most cars turn on the AC automatically when the front defogger is on (it dries out the air which helps defog your windshield faster)

When you accelerate rapidly - the air compressor on most newer vehicles automatically cuts out - to temporarily reduce the load on your engine.

Smelling it during acceleration and after stopping - it's possible the smell is there the whole time - but when you're accelerating hard you're likely coming from a slow speed / stop - so this odor that's there the whole time, builds up. (once you're driving - the air movement dilutes the odor)

Does this happen from a cold start - or does it have to be running for a period of time first?

What type of burning smell? Rubber? Oil? Fried electronics? Is it a sweet smell? Acrid?
Click to expand...

Regarding your questions, I have never noticed it upon initially starting the car - it usually comes about after it's been running, and it's not every time it runs.

If I had to specifically say what it smells like, I think fried electronics would fit the description best.
 
"Burning" smell is pretty fauge...

Anybody else think that it could possibly just be hot coolant on the passenger floormat?

OP, is there any fluid appearing on your floorboards? If so, maybe a heater core issue.
 
ipsb11: There's been a lot of snow in Ohio and the floormats are constantly soaked from all of it, however I didn't notice any before the snow.

iJohnHenry: Not that I know of...
 
Floormats that get soaked and dry a few times can smell really bad. The odor could be activating when the interior warms up a bit. Run them through the washing machine, if this is the case.
 
senseless said:
Floormats that get soaked and dry a few times can smell really bad. The odor could be activating when the interior warms up a bit. Run them through the washing machine, if this is the case.
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As I said above, I noticed the smell before the floormats were going through wet and dry cycles. Also, I doubt that it would produce a burning smell. It'd be more of a musty smell if anything, no? Thanks anyways though :)
 
A year later and I have just taken the car in for another problem. I mentioned the smell and after the mechanic had it for a day, he told me the smell was from a bad valve cover that is allowing just a small amount of fluid to leak onto the manifold and on to the exhaust.
 
Gregg2 said:
Ah, then you're not far from a mechanic. Take it in and have the pros diagnose the cause for you.
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ideal.dreams said:
A year later and I have just taken the car in for another problem. I mentioned the smell and after the mechanic had it for a day, he told me the smell was from a bad valve cover that is allowing just a small amount of fluid to leak onto the manifold and on to the exhaust.
Click to expand...

There you go!
Those auto mechanics know lots about, um, autos.
 
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