[gt11990]

So I have a f32 2016 only at 17k petrol

But recently I randomly get this bad smell like something has died or a fart or egg

But it only comes in the mornings or when u start the car but not always and only when I put the heaters on

I read that it my be my cat but it's still new low mileage and use good fuel

But then if it's the cat it should do the smell always even if the heating is not on but this just happens when the heating is on but then after a few seconds it disappears and I never smell it again till my next journey but not always next journey like this morning had no smell

Can someone please let me know what it could be and how I could check to pin point what it is

Thank you

[dmaxdmax]

That sounds like a classic cat issue...that or your cabin air filter needs a change. Also, some fuels with the winter formula do smell different--I've noticed that before. I wouldn't worry about it unless you get a code.

[chowser51]

If it's not the cat, when was the last time you changed the cabin filter?
If you do change the cabin filter, take it out and blow some lysol / disinfectant through the system before putting in the new cabin filter.

[gt11990]

I'll have to try the cabin filter over the weekend and see if that changes it

I thought it could be cat but the car had a end of warranty check and all was good unless bmw did not do their job properly or just didn't check the cat

[dmaxdmax]

Originally Posted by gt11990

I'll have to try the cabin filter over the weekend and see if that changes it

I thought it could be cat but the car had a end of warranty check and all was good unless bmw did not do their job properly or just didn't check the cat

It could be the formula of gas too. When you start up cold your cat hasn't caught up to cleaning things yet...so it doesn't sound like it's a serious issue...and the cat warranty 'was' something like 10 or 20 years on my e46...I suspect it'd be covered for a long time.

[exE36M3]

2016?... Change out the cabin filter. About a 30 min job at worst. Well that and putting your body into a weird position to get to it.

[Billfitz]

Various wee beasties grow in the heater core and AC evaporator. They create an odor that stays in the heater/AC unit until the car starts, and the fan blows that odor in your face. It subsides after a bit, only to build up the next time the car sits and there's no air movement through the coils. Changing the filter helps, but the coil must be periodically cleaned, especially if you live in a damp climate. I use this every spring, when I'm under the car anyway to change the oil:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[gt11990]

Originally Posted by Billfitz

Various wee beasties grow in the heater core and AC evaporator. They create an odor that stays in the heater/AC unit until the car starts, and the fan blows that odor in your face. It subsides after a bit, only to build up the next time the car sits and there's no air movement through the coils. Changing the filter helps, but the coil must be periodically cleaned, especially if you live in a damp climate. I use this every spring, when I'm under the car anyway to change the oil:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Thank that does look promising and explains pretty much my dilemma i shall get to cleaning tomorrow and hopefully the smell never comes back 😂

[evdok]

I had a damp smell randomly & I bought this.

I kid you not its one of the best things I've bought that works!

[Billfitz]

Originally Posted by gt11990

i shall get to cleaning tomorrow and hopefully the smell never comes back 😂

It will, eventually. When it does clean the coils again.

[dmaxdmax]

Originally Posted by evdok

I had a damp smell randomly & I bought this.

I kid you not its one of the best things I've bought that works!

You don't happen to have a link to that ozone generator he used, do you? There are a number of little plug in ones, but I doubt they'd come close to what that thing did.

[evdok]

https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1

Currently not available

[Billfitz]

An ozone generator will clean the air in the car, but it won't prevent more stink from being created in the heating/cooling unit. An 'always on' unit is no solution, as ozone itself is potentially harmful. It's recommended that generators not be used when the car is occupied. Periodic cleaning of the coils kills the source of the stink, literally, at the source.

[Hangman4358]

Originally Posted by Billfitz

An ozone generator will clean the air in the car, but it won't prevent more stink from being created in the heating/cooling unit. An 'always on' unit is no solution, as ozone itself is potentially harmful. It's recommended that generators not be used when the car is occupied. Periodic cleaning of the coils kills the source of the stink, literally, at the source.

I have been having this problem on and off for a while but I have yet to find any DIY guide that actually shows where the coils are located on our cars! Maybe I am just extra dumb.

[Billfitz]

They're not easily accessible. There is a drain tube that comes down in the transmission tunnel. Coil cleaner is injected into that tube. That's the easy part, the PITA is you have to remove the under body shield to get at it. I think when I next do mine I'm going to drill a hole in the shield and extend the tube through it. There are youtube videos showing how o inject the cleaner, though none specific to BMW that I know of.

[gt11990]

I can confirm that even after changing the cabin filter and using the spray to clean the system the smell is still there at first it was light now it's slowly coming back stronger only when heating is on low and hitting the feet however when its on full blast no smell ever comes any ideas

[scoopy]

Originally Posted by gt11990

I can confirm that even after changing the cabin filter and using the spray to clean the system the smell is still there at first it was light now it's slowly coming back stronger only when heating is on low and hitting the feet however when its on full blast no smell ever comes any ideas

did you find the solution for this? sorry

[dmaxdmax]

I'll just say that I've found that by turning the AC off about 5 mins. before I'm home (or stopped) that it seems to keep odors down.

The evaporator warms to air temp and dries off so mold and stuff doesn't grow on otherwise moist coils.

...that's once you take care of the smell to begin with.

[AspektUSA]

https://www.amazon.com/nextzett-9611...omotive&sr=1-1

This stuff works great to clean out evap coils and climate systems.

Also replace your pollen filter with a charcoal one while you're at it.

https://www.fcpeuro.com/products/bmw...119237555-blue

[gt11990]

Originally Posted by scoopy

did you find the solution for this? sorry

Nope none at all it seems to have gone now but sometimes comes rarely and suddenly weird right also am always using high quality petrol now which is more expensive

[Wires]

Some fuel has high Sulphur content which will stink as well. It is a different smell from rotten eggs though. That sounds like a O2 sensor issue. You sure it's the heaters and not just the cold start where it revs higher?