Bad egg smell

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Veg

New Member
Joined
Nov 2, 2014
Messages
19
Car
W219
My 320 CDI has developed a smell not unlike a catalytic converter bad egg whiff, generally after a longish run. Seems like it comes through the air vents because if I switch the climate control off it goes away. And no I've not eaten sprout and egg curry!

I suspect diesel is hitting the cat probably through over fueling but I have added Millers recently so could this be it......???
 
Battery gassing through alternator over-voltage?
Put a multimeter across the battery terminals while the engine is running - expect no more than about 14.5V.
 
If its a W211 or.W203 then there is a high chance its due to bacteria/fungus build-up in the screenwash reservoir. Common in the above models apparently.

Does it come only with hot air on?

A quick check is to open the reservoir lid and smell the inside of the reservoir, ideally when engine is hot. If the same eggy smell can be smelled in the reservoir, then definitely that's the cause.

Since the pollen filter is directly above the screenwash tank, the smell travels into the air system. It must be the same.pollen filter design in the CLS but not sure.

My dad had this same problem in his W211 320CDI. We put two tankfuls of neat screenwash fluid and took it out through the jets but no luck.

I read online somewhere that put a weak solution of water+bleach in tank and leave it.overnight - we did not try this so not sure.

Hope this helps
 
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Yes it's a CLS and the arrangement is the same and I've been using the screen wash just as I come off the motorway. Must be some anti bacterial fluid in the cleaning cupboard!
 
Yes it's a CLS and the arrangement is the same and I've been using the screen wash just as I come off the motorway. Must be some anti bacterial fluid in the cleaning cupboard!

That's also another way to check - Sometimes when releasing screenwash fluid through the jets, the eggy smell slowly travels into the cabin.

I would put my money on bacteria growth within the screenwash tank, releasing bad odours, certainly, if the odour is most noticeable when hot air is turned on.

Some say a good quality screenwash fluid prevents bacteria build-up. Not sure about this but I convinced my dad to only buy MB screenwash fluid for his Mercedes, as recommended on this forum by someone.
 
Mbenz1 you were spot on! Some anti bacterial disinfectant going in which should cure it. Amazing that the smell is so intense too and without your help I would be looking at the cats and over fueling etc.....cheers
 
Mbenz1 you were spot on! Some anti bacterial disinfectant going in which should cure it. Amazing that the smell is so intense too and without your help I would be looking at the cats and over fueling etc.....cheers

Good to hear its the tank and not anything more serious like Cats etc... Be careful with the concentration of what ever fluid you will put in, as I assume there will be a sensor/wires or something delicate in there :dk: good luck :)
 
I had this problem. I use the pink ready mix from halfords. Never had a problem since

Sent from my iPhone using MBClub UK
 
Best thing is to stick to one brand of screen wash. Specifically don't mix the super concentrated types with normal stuff-my dad did and it turned to a gel in the bottom of the bottle - that's when the bad smell started!
 
Milton sterilizing tablets,
also good to use in the bath when you have massage jets whirlpool etc the water left in the pump system remains sterile when left for long time periods.
 
Mind the bleach solutions chaps, Bleach will quickly rot the rubber bits.
 

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