Cylinder 4 and 8
Thread Starter
Newbie
Joined: Oct 2021
Posts: 14
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From: Central Coast California
2015 GL63
Cylinder 4 and 8
I have a 2015 GL63 (M157) with about 99k miles. I just did the spark plugs on them. I went ahead and stuck the camera inside all of 8 cylinders and noticed cylinder 4 and 8 with some oil. Even the spark plugs had some oil residue. All the other cylinders were dry with spark plugs. Can anyone help me to help reduce that and if there is something I need to look into?
Thanks.
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Joined: Jun 2004
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Check this thread out:
https://mbworld.org/forums/w212-amg/...72k-miles.html
And check out the sticky:
https://mbworld.org/forums/w212-amg/...fixes-diy.html
https://mbworld.org/forums/w212-amg/...72k-miles.html
And check out the sticky:
https://mbworld.org/forums/w212-amg/...fixes-diy.html
Last edited by PeterUbers; Mar 9, 2025 at 12:50 AM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
assessment
-- Can we guess how oil is getting into Cyl.4+8:
stuck rings or damaged walls ?
-- How much oil is the engine consuming:
a little or a lot??
-- What conditions are cylinder walls in:
slick/scored??
-- What sort of oiling do you provide: ??
Sce schedule, oil grade, oil type,...
-- Strange combo 4+8 instead of 1+5...:
near tranny instead of away from load.
-- How are overall performance ??
-- Are ignition components in good repair??
plug + boots + coils, what gap now on old plug?
I recommend you switch to a cleaner API-SP oil of your choice and replace 2x upstream Lambda shortly.
stuck rings or damaged walls ?
-- How much oil is the engine consuming:
a little or a lot??
-- What conditions are cylinder walls in:
slick/scored??
-- What sort of oiling do you provide: ??
Sce schedule, oil grade, oil type,...
-- Strange combo 4+8 instead of 1+5...:
near tranny instead of away from load.
-- How are overall performance ??
-- Are ignition components in good repair??
plug + boots + coils, what gap now on old plug?
I recommend you switch to a cleaner API-SP oil of your choice and replace 2x upstream Lambda shortly.
Last edited by CaliBenzDriver; Mar 9, 2025 at 01:36 AM.
Thread Starter
Newbie
Joined: Oct 2021
Posts: 14
Likes: 3
From: Central Coast California
2015 GL63
Thank you @PeterUbers
Thread Starter
Newbie
Joined: Oct 2021
Posts: 14
Likes: 3
From: Central Coast California
2015 GL63
@CaliBenzDriver
not sure how the oil is getting in. All other cylinders were bone dry as the spark plugs.
The cylinder walls were pretty good. No scoring like I’ve seen online at least.
It may use up to a quart or 2 every 5-6k miles. Depending how I’m driving it. This last time I did let it go a little longer on mileage.
I using Mobile 1 0W-40 oil.
The car drives good. Pulls and sounds good.
Replaced boots. The coils were all good. I did not measure gap on the old plugs. Just the new ones that I installed. Torqued to spec.
Thanks.
not sure how the oil is getting in. All other cylinders were bone dry as the spark plugs.
The cylinder walls were pretty good. No scoring like I’ve seen online at least.
It may use up to a quart or 2 every 5-6k miles. Depending how I’m driving it. This last time I did let it go a little longer on mileage.
I using Mobile 1 0W-40 oil.
The car drives good. Pulls and sounds good.
Replaced boots. The coils were all good. I did not measure gap on the old plugs. Just the new ones that I installed. Torqued to spec.
Thanks.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
lucky... CPV
@GL M157
The difference between normal cylinders and 4/8 are so distinctly different... I think we have reason to suspect a known "oil provider".
The cylinders wall are not perfect but are rather good overall.
standard leaky rings... normal (not huge)
What do we know about your Crankcase Positive Ventilation status... replace CPV components!
I think it's feeding your lost 2Quarts through the INTAKE or something else is feeding Cyl.4/8 from the top, not from the walls.
Luckily, the failed CPV is actually helping keep crankcase pressure lower thus helping keep other cylinders cleaner the way they are.
While replacing CPV replace HPFP "ROLLERS* preventatively to preserve your Bank1 camshaft and chain.
The difference between normal cylinders and 4/8 are so distinctly different... I think we have reason to suspect a known "oil provider".
The cylinders wall are not perfect but are rather good overall.
standard leaky rings... normal (not huge)
What do we know about your Crankcase Positive Ventilation status... replace CPV components!
I think it's feeding your lost 2Quarts through the INTAKE or something else is feeding Cyl.4/8 from the top, not from the walls.
Luckily, the failed CPV is actually helping keep crankcase pressure lower thus helping keep other cylinders cleaner the way they are.
While replacing CPV replace HPFP "ROLLERS* preventatively to preserve your Bank1 camshaft and chain.
Last edited by CaliBenzDriver; Mar 9, 2025 at 02:55 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Jose, I've reviewed your oil lab test.
As lab noted numbers are in expected range (viscosity, aluminum, moly/boron/zinc/calcium) for stock 0w40.
Engine oil selection being a personal choice, the stock is working well.
You may want to... shorten 8.5kMi oil service to half that.
This would preserve the oil properties, preventing calcium sludge and viscosity shear.
Improving heat mgt will preserve components life including new CPV.
As lab noted numbers are in expected range (viscosity, aluminum, moly/boron/zinc/calcium) for stock 0w40.
Engine oil selection being a personal choice, the stock is working well.
You may want to... shorten 8.5kMi oil service to half that.
This would preserve the oil properties, preventing calcium sludge and viscosity shear.
Improving heat mgt will preserve components life including new CPV.
Last edited by CaliBenzDriver; Mar 9, 2025 at 02:53 PM.
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Thread Starter
Newbie
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From: Central Coast California
2015 GL63
Thank you so much @CaliBenzDriver .
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Joined: Oct 2018
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From: NYC
AMG
Oil in cyl 4 according to benz is a sign of the oil separator/ breather on the passenger side rear of the head needing replacement. A bad unit will put oil on the pass side of the intake manifold where the cyl that gets the oil is first in line, cyl 4, but enough i can see it spreading to the other side of the manifold being sucked into 8 aswell. Good place to start.
