Exhaust Smoking W Smell only in idle!?
Thread Starter
Junior Member
Joined: Nov 2023
Posts: 44
Likes: 7
GLE 400
Exhaust Smoking W Smell only in idle!?
Hey everyone I have a puzzling issue, 2019 W166 GLE hit 100k.
Most of the cars life has been driving smooth highway miles, no SES/CEL on, no codes on OBD scanner yet for some reason whenever I idle for about 5 to 10 minutes or so I have some white smelly smoke coming out of the exhaust. It only happens in idle. Goes away when put in drive.
I noticed it happens only when idling for a few minutes and does not smoke at all while driving or even in when at a stop while holding breaks with car in drive.
At first I feared head gasket, did a test and thankfully wasn’t that.
I have no visible oil leaks and I’m not loosing coolant….
I’ve used Techron complete fuel system cleaner thinking maybe it’s a faulty fuel injector but it’s been a week and no change. I’m thinking of trying Techron Fuel Injection cleaner next…..
But doing some more research leads me to thinking is it possible to be a bad PCV? Or maybe EGR? I’m simply puzzled, figured I’d share here to get some other suggestions?
Thanks in advance 🙏🏼
Most of the cars life has been driving smooth highway miles, no SES/CEL on, no codes on OBD scanner yet for some reason whenever I idle for about 5 to 10 minutes or so I have some white smelly smoke coming out of the exhaust. It only happens in idle. Goes away when put in drive.
I noticed it happens only when idling for a few minutes and does not smoke at all while driving or even in when at a stop while holding breaks with car in drive.
At first I feared head gasket, did a test and thankfully wasn’t that.
I have no visible oil leaks and I’m not loosing coolant….
I’ve used Techron complete fuel system cleaner thinking maybe it’s a faulty fuel injector but it’s been a week and no change. I’m thinking of trying Techron Fuel Injection cleaner next…..
But doing some more research leads me to thinking is it possible to be a bad PCV? Or maybe EGR? I’m simply puzzled, figured I’d share here to get some other suggestions?
Thanks in advance 🙏🏼
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,243
Likes: 932
From: New Orleans Area
2015 E400 Sedan
what does it smell like?
White tends to mean coolant and/or water vapor.
Does engine temp have any effect on smoke? cold engine more smoke or less versus hot?
What about outside air temp and humidty? cold, medium or hot? dry or your glasses fog up humid?
What test was done to rule out head gasket?
White tends to mean coolant and/or water vapor.
Does engine temp have any effect on smoke? cold engine more smoke or less versus hot?
What about outside air temp and humidty? cold, medium or hot? dry or your glasses fog up humid?
What test was done to rule out head gasket?
Thread Starter
Junior Member
Joined: Nov 2023
Posts: 44
Likes: 7
GLE 400
what does it smell like?
White tends to mean coolant and/or water vapor.
Does engine temp have any effect on smoke? cold engine more smoke or less versus hot?
What about outside air temp and humidty? cold, medium or hot? dry or your glasses fog up humid?
What test was done to rule out head gasket?
White tends to mean coolant and/or water vapor.
Does engine temp have any effect on smoke? cold engine more smoke or less versus hot?
What about outside air temp and humidty? cold, medium or hot? dry or your glasses fog up humid?
What test was done to rule out head gasket?
I did a chemical test for the head gasket, color stayed blue and I waited for over 10 min testing again and again on two different occasions. Color stays solid so it’s not the head gasket….
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,243
Likes: 932
From: New Orleans Area
2015 E400 Sedan
take pic - is a cloud of smoke like a battleship trying to hide behind smoke screen? or ??
Could be something to do with moisture in exhaust if very little smoke.
ANything else different?
less power? different exhaust sound?
ANy fluid leaks?
What does it smell like?
IF tiny amount of smoke only after idling for few mins could be miniscule amount of liquid
Could be something to do with moisture in exhaust if very little smoke.
ANything else different?
less power? different exhaust sound?
ANy fluid leaks?
What does it smell like?
IF tiny amount of smoke only after idling for few mins could be miniscule amount of liquid
Thread Starter
Junior Member
Joined: Nov 2023
Posts: 44
Likes: 7
GLE 400
take pic - is a cloud of smoke like a battleship trying to hide behind smoke screen? or ??
Could be something to do with moisture in exhaust if very little smoke.
ANything else different?
less power? different exhaust sound?
ANy fluid leaks?
What does it smell like?
IF tiny amount of smoke only after idling for few mins could be miniscule amount of liquid
Could be something to do with moisture in exhaust if very little smoke.
ANything else different?
less power? different exhaust sound?
ANy fluid leaks?
What does it smell like?
IF tiny amount of smoke only after idling for few mins could be miniscule amount of liquid
No loss off power, no difference in exhaust sound, no fluid leaks that are visible to me….
I’ll try and take pictures and a video and post it, actually not a bad idea 🙏🏼👍🏼
Thread Starter
Junior Member
Joined: Nov 2023
Posts: 44
Likes: 7
GLE 400
Finally happened again, I was able to record it.
video: https://jmp.sh/x8JNqN1i
now keep in mind, soon as I turn off the car and turn it back on, it’s gone. No smoke again.
video: https://jmp.sh/x8JNqN1i
now keep in mind, soon as I turn off the car and turn it back on, it’s gone. No smoke again.
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,243
Likes: 932
From: New Orleans Area
2015 E400 Sedan
looks like water vapor -
is it cold and humid?
does it happen after engine up to temp?
What does it smell like? (DEAD RAT?)
DO you park up hill or down hill or in flat garage? IE any dew or collected water in exhaust move towards engine or back out tail pipe when off?
IF it was me and under factory bumper to bumper warranty I would take it in to get logged on file so in case it does tur into anything they should pay for it since you brought it in.
I really think it is just morning dew steaming out tips
is it cold and humid?
does it happen after engine up to temp?
What does it smell like? (DEAD RAT?)
DO you park up hill or down hill or in flat garage? IE any dew or collected water in exhaust move towards engine or back out tail pipe when off?
IF it was me and under factory bumper to bumper warranty I would take it in to get logged on file so in case it does tur into anything they should pay for it since you brought it in.
I really think it is just morning dew steaming out tips
Trending Topics
Thread Starter
Junior Member
Joined: Nov 2023
Posts: 44
Likes: 7
GLE 400
looks like water vapor -
is it cold and humid?
does it happen after engine up to temp?
What does it smell like? (DEAD RAT?)
DO you park up hill or down hill or in flat garage? IE any dew or collected water in exhaust move towards engine or back out tail pipe when off?
IF it was me and under factory bumper to bumper warranty I would take it in to get logged on file so in case it does tur into anything they should pay for it since you brought it in.
I really think it is just morning dew steaming out tips
is it cold and humid?
does it happen after engine up to temp?
What does it smell like? (DEAD RAT?)
DO you park up hill or down hill or in flat garage? IE any dew or collected water in exhaust move towards engine or back out tail pipe when off?
IF it was me and under factory bumper to bumper warranty I would take it in to get logged on file so in case it does tur into anything they should pay for it since you brought it in.
I really think it is just morning dew steaming out tips
appreciate the reply and wish it was morning due but unfortunately I don’t believe it is.
parking is flat straight, doesn’t happen at all during start up, engine is up to temp, and it doesn’t happen often. Also if you look at the video the way the smoke is coming out isn’t smooth like morning dew or water….
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Super Member
Joined: Nov 2007
Posts: 500
Likes: 137
From: Washington D.C. area
16 GLE400 4matic
Did you check the coolant level on both reservoirs?
Did you check the oil level?
What was the outside temperature? Mine does this when it's cold
What does it smell like?
Did you check the oil level?
What was the outside temperature? Mine does this when it's cold
What does it smell like?
MBWorld Fanatic!
Joined: Feb 2017
Posts: 2,296
Likes: 1,204
From: Baltimore County, MD
'13 s212 63 p30. '06 LX470
You mentioned not losing coolant, but are you losing oil? What does the smoke smell like, and there any deposit or drips onto the ground from that smoke or cede station? Do you think your symptoms match up with videos you have watched of leaky valve stems or valve stem seals? If so, apparently a product from the brand forte could help while deciding on your longer term fix. BMW guys use this for many of their crappy leaking engines.
Newbie
Joined: Jun 2024
Posts: 8
Likes: 0
W166 GLE400
Thanks for the video, it definitely doesn't look like water vapour on a cold morning. Your title says "smell", and post says "smelly", but there's no descriptor of the smell itself. This would be the biggest hint as to what your problem is.
Member
Joined: Apr 2021
Posts: 231
Likes: 91
From: Mitchell, SD, U.S.
2016 GLE 300d 4-Matic
That smoke looks like it has a blue-ish color to it to my eyes. That would be oil. If it's only there after you've started it and then it goes away, the usual cause is valve stem seals.
