Rotten egg smell and loud rattle

Slick_FThirty · 01-11-2020, 05:57 PM

Hello,

Last night, I was driving my 2013 328i, and was pushing relatively hard for some fun, after the car was warmed up of course. However, when I arrived home and parked in the garage, I noticed a very strong smell of rotten eggs. At this time, I did not notice a rattle. I turned the car off and then back again, and there was a decently loud and obvious rattle for about 30 seconds and eventually went away as the car was idling.

This seems like an obvious case of catalytic failure, however today, I have not heard this rattle or did not smell rotten eggs. I have never experienced this except that one time.
For what it's worth, it was very cold last night, about -15 Celsius.

Thoughts? Any worries I should or should not have?

Edit: completely stock car. No errors or check engine lights

TDOTF30 · 01-12-2020, 08:43 PM

Sounds like an exhaust leak to me. Temperature may have a role in that, rapid cooling of the exhaust while the car is off, followed by the restart. Although I've personally never had an issue like that and we get pretty cold winter in Canada.

blumagic · 01-13-2020, 09:09 AM

Check the exhaust flap near the muffler tips. the rattle is most likely that being lose or the pin blew off

meltbox · 01-14-2020, 06:16 PM

That sounds exactly like the ceramic element in your cat broke and now sometimes rattles against the housing or something. Smell also matches it. Strange though if you're stock...

I guess see if it comes back. If it never rattles after running for a while I would have to say it isn't the cat despite all the typical symptoms of a cat.

Slick_FThirty · 02-01-2020, 03:14 PM

I haven't yet experienced the rattle again, but now that it's been warmer and have been driving with the windows down, I noticed there is a rotten egg smell sometimes (not always) after accelerating in a more spirited fashion. During gentle acceleration, I don't seem to notice a smell.
I don't smell it while idling, or while revving the engine at idle.

No errors noticed on the dash.

Is this a problem? Thoughts? Potential fixes?

Slick_FThirty · 02-02-2020, 12:35 PM

I noticed bmw has an 8yr/130000km warranty on cats. What criteria needs to be satisfied for replacement?

Gen13 F36 · 02-06-2020, 12:56 AM

Are you sure you didn't forgot your lunch bag in the car.

01-11-2020, 05:57 PM	#1
Slick_FThirty First Lieutenant 125 Rep 326 Posts Drives: 13' BMW 328i Xdrive Join Date: Oct 2019 Location: Canada iTrader: (0)	Hello, Last night, I was driving my 2013 328i, and was pushing relatively hard for some fun, after the car was warmed up of course. However, when I arrived home and parked in the garage, I noticed a very strong smell of rotten eggs. At this time, I did not notice a rattle. I turned the car off and then back again, and there was a decently loud and obvious rattle for about 30 seconds and eventually went away as the car was idling. This seems like an obvious case of catalytic failure, however today, I have not heard this rattle or did not smell rotten eggs. I have never experienced this except that one time. For what it's worth, it was very cold last night, about -15 Celsius. Thoughts? Any worries I should or should not have? Edit: completely stock car. No errors or check engine lights __________________ If you can imagine it, you can achieve it. If you can dream it, you can become it.
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01-12-2020, 08:43 PM	#2
TDOTF30 Enlisted Member 7 Rep 40 Posts Drives: F30 328i xDrive Join Date: Nov 2018 Location: Toronto iTrader: (0)	Sounds like an exhaust leak to me. Temperature may have a role in that, rapid cooling of the exhaust while the car is off, followed by the restart. Although I've personally never had an issue like that and we get pretty cold winter in Canada.
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01-13-2020, 09:09 AM	#3
blumagic Second Lieutenant 309 Rep 271 Posts Drives: 2014 328i xdrive , 2013 SHO Join Date: Mar 2019 Location: West Lafayette, IN iTrader: (0)	Check the exhaust flap near the muffler tips. the rattle is most likely that being lose or the pin blew off
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01-14-2020, 06:16 PM	#4
meltbox Private First Class 43 Rep 170 Posts Drives: 2014 328xi GT (F34/N20) Join Date: Sep 2018 Location: Michigan iTrader: (0)	That sounds exactly like the ceramic element in your cat broke and now sometimes rattles against the housing or something. Smell also matches it. Strange though if you're stock... I guess see if it comes back. If it never rattles after running for a while I would have to say it isn't the cat despite all the typical symptoms of a cat.
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02-01-2020, 03:14 PM	#5
Slick_FThirty First Lieutenant 125 Rep 326 Posts Drives: 13' BMW 328i Xdrive Join Date: Oct 2019 Location: Canada iTrader: (0)	I haven't yet experienced the rattle again, but now that it's been warmer and have been driving with the windows down, I noticed there is a rotten egg smell sometimes (not always) after accelerating in a more spirited fashion. During gentle acceleration, I don't seem to notice a smell. I don't smell it while idling, or while revving the engine at idle. No errors noticed on the dash. Is this a problem? Thoughts? Potential fixes? __________________ If you can imagine it, you can achieve it. If you can dream it, you can become it.
	Appreciate 0 Quote

02-02-2020, 12:35 PM	#6
Slick_FThirty First Lieutenant 125 Rep 326 Posts Drives: 13' BMW 328i Xdrive Join Date: Oct 2019 Location: Canada iTrader: (0)	I noticed bmw has an 8yr/130000km warranty on cats. What criteria needs to be satisfied for replacement? __________________ If you can imagine it, you can achieve it. If you can dream it, you can become it.
	Appreciate 0 Quote

02-06-2020, 12:56 AM	#7
Gen13 F36 Brigadier General 1599 Rep 3,752 Posts Drives: 428i Gran Coupe Join Date: Nov 2017 Location: Los Angeles, CA iTrader: (1)	Are you sure you didn't forgot your lunch bag in the car.
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