Burning smell

[devonmercgirl]

Sorry if this has been posted before, when we have drove for a while maybe and we have to stop or slow down for traffic etc we notice a burning smell coming through the air vents, we have checked for oil leaks and nothing, there is no noises etc just the smell of burning, once cooled down its fine again until we go on a run and the car slows down in traffic/standstills anyone have any ideas on what this could be? Many thanks

 

[John]

I'd have a look at your brakes for one - it could be a seized caliper causing a pad to rub which would get very hot and cause a burning smell.

You can tell because discs normally have a uniform look - when a caliper is seized and a pad is rubbing - you get a 'smeared' look where the pad touches...

You might only notice it slowing or stopping due to the wind current taking the smell behind the car.

Or could be discs needing replacement i.e. too thin?

 

[devonmercgirl]

Ok I will get the other half to look tomorrow, yeah the smell is just when we slow down and if the heaters are on high? The temp gauge sits at 80 or below is this right? Doesn't happen every time but I would say 90% of the time it does. We also have the air vent reset clicking noise for 30 seconds if that has anything to do with it but the smell may not be to do with the vents but brakes as u said. I will get him to look tomorrow' thanks for replying

 

[andy27168]

Hi,
When you checked for leaks did you remove the air cleaner assembly? Not knowing what year your 500 is if its a M113 V8 it could well be leaking breather covers on the engines rocker covers, drips down onto the exhaust manifolds, very common problem on the M112 V6 and M113 V8's, as the breather covers are only sealed with a sealant, no gasket.

 

[devonmercgirl]

Hi, it's a 2002 clk500 v8 if that's any help I don't know much about that sort of stuff I think the other half is gonna have a proper look tomorrow at what has been mentioned we just wanted any info on possible outcomes so thank you both for your replies

 

[SavMan]

Hi,
When you checked for leaks did you remove the air cleaner assembly? Not knowing what year your 500 is if its a M113 V8 it could well be leaking breather covers on the engines rocker covers, drips down onto the exhaust manifolds, very common problem on the M112 V6 and M113 V8's, as the breather covers are only sealed with a sealant, no gasket.

This is the most likely it will have some kind of leak dripping straight onto the manifold so wont be easily spotted as it will evaporate when the manifolds is hot.

 

[devonmercgirl]

Hi thank you for your responses we've had someone look at it and he said he can't see anything and all he said was that the cats heat to 400degrees and it could be the smell off of that??!.. But I'm not so sure, there didn't seem to be any signs of oil. Thank you for your replies

 

[John]

Has the exhaust recently been replaced?

Sometimes new exhausts smell when they first get hot a few times.

If not, must only have been a temporary thing which has resolved itself - or it will come back and bite you on the RS and then you will probably know!

 

[BTB 500]

it will come back and bite you on the RS

Only if you have an Audi or a Ford

 

[BlackC55]

This is typical symtoms for a carrier bag stuck on the cats

 

[devonmercgirl]

No the car has been on a garage ramp and nothing is stuck, we've had the car 5 months ish and we haven't had the exhaust done! Smells horrible at times mainly happens if I'm sat at lights for a long period of time then the smell creeps in the vents. But once I'm moving it stops or the wind blows the smell away from the car. They've looked for oil leaks etc but can't spot anything.

 

[devonmercgirl]

And itonly normally happens once the car has "warmed" up! Never when it's cold :-/ if that's any help

 

[BlackC55]

Check the rocker covers for leaks. Remove the engine cover and you should see if there are any oil leaks.

 

[devonmercgirl]

Ok I will get the other half to look tomorrow - I'm useless ha! Thank you