Burning Smell coming thru air con

[IrishPhoenix]

the last two days (very infrequent) there has been a raw burning smell coming thru the air con (when on a mild heat 21 or so). It smells more like an engine smell though. Any ideas what causes this?

[gtoirl]

I used to get a smell like this in my Mazda when the engine coolant was low. Ended up being a cracked radiator.

[CJ]

Have you checked the passanger footwell for dampness (coolant)? Hope it ain't the heater matrix....

CJ

[Myfeckin FTO]

You need to get this checked out.
Possibilities include - 1: A pully/tensioner on the Power steering/aircon/Alt belt has seized and is burning your belt as it rotates..
2: You have a leak of fluid onto your exhaust - may be a leaky rocker gasket (a squeeze on the bolts maybe enough to stop) or may be another type of fluid or grease reaching the exhaust from a worn part.
3: Brake pads ?? Sticky caliper?

Is this more noticeable after the car is driven hard or can it happen first thing in the morning?

[IrishPhoenix]

noticed it after coming back from carlow. stopped at my house then for 2 hours, smell came later on that night when going to the shops. just for a second. Thanks for the advice, if it happens again i'll have to get someone to look at it as I'm not familiar with mechanics

[Grace]

I noticed this smell a few times before changing my belts and now that I read this thread I'm wondering if the PS/AC belt might have been the cause.
Here's a picture its condition before the change:

Notice that the bit that is off the guide is threaded. Now I'm guessing this might have been rubbing against something to cause the occasional burning smell

[jt]

Hi folks,

Was there ever any conclusion on this issue?

I've recently noticed a burning smell coming from mine, although I've checked the coolant etc. and all seems fine, and there're no signs the engines overheating (6 hours stuck in traffic last week and the temp gauge remained steady). It's been around for about a month or so now.

Not sure if it's related, but the power delivery is a little inconsistent when I accelerate, so could it be the clutch or gearbox maybe, or a sign that I have a sticky caliper?

1: A pully/tensioner on the Power steering/aircon/Alt belt has seized and is burning your belt as it rotates..
2: You have a leak of fluid onto your exhaust - may be a leaky rocker gasket (a squeeze on the bolts maybe enough to stop) or may be another type of fluid or grease reaching the exhaust from a worn part.

What do I need to look for if one of these is the problem?

Many thanks in advance (and thanks again for all the help I've had in the past from this forum).

Jon

EDIT:

Forgot to mention, the burning smell doesn't come through the air con in my situation, I can just smell it when I get out of the car.

[CJ]

Not sure if it's related, but the power delivery is a little inconsistent when I accelerate, so could it be the clutch or gearbox maybe, or a sign that I have a sticky caliper?

Jon, you would know if the clutch is acting up when gearing, declutching etc. If one of the calipers is seized, the brakes will get very hot - place your hand near (no on!) the brakes after a drive to see if you can ascertain if this is the issue.

Do you only get the smell when the aircon is on / when the window is open? Is the odour apparent under the bonnet? Can you describe the odour?

CJ

[Bernard]

If one of the calipers is seized, the brakes will get very hot - place your hand near (no on!) the brakes after a drive to see if you can ascertain if this is the issue.

CJ

When one of my calipers was stuck I got a burning smell too, also a tinny sounding tick coming from the wheel cooling.
If it's a caliper the whole wheel will be warm (was in my case anyway).

[jt]

Haven't noticed any clicking, I'll go for a drive later and see what the brake/wheen temps are like after. There's no smell coming through from the air-con, so doesn't seem to be related to that.

One thing I noticed when I was stuck in traffic last week - the rain on my bonnet was evaporating into steam, is it normal for the engine to heat the bonnet up this much? Never noticed this before.