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2014 C300 W276.9 140k miles
Girlfriend bought it for me to fix
Doing the left intake adjuster replacement and saw the following on the back of the intake cam lobes and in exhaust front lobe. It is NOT deposit but pitting into the lobe.
Have not pulled the right bank (wasn't planning on it). Haven't pulled the cam to see the rollers yet.
Any opinion on the wear? Wasn't planning on replacing it but???
Intake rear cylinder both lobes Intake third lobe from back
Exhaust side first lobe from front
that is not wear.
That is damage from lifter or bad Camshaft
I would replace everything in heads. Cam, Cam bearings, maybe even valves and springs.
Kinda looks like the springs were soft and/or over redline and valves floated and pounded into the lobes
What does it look like with Cam shaft removed? STuff under.
that is not wear.
That is damage from lifter or bad Camshaft
I would replace everything in heads. Cam, Cam bearings, maybe even valves and springs.
Kinda looks like the springs were soft and/or over redline and valves floated and pounded into the lobes
What does it look like with Cam shaft removed? STuff under.
that's what I was worrird about. Cam removal is the next step. I removed the right cover to see that side too and it looked fine on what I could see but going to spin the engine today to see what the lobes look like (was waiting on paint to dry).
I wonder how the camshaft 3x fuel pump lobes look like? (pump + roller + PCV kit)
cam profile split in half...
You found Bank2 extensive damages to both intake/exhaust camshafts nearest to oil supply side.
if there's one good thing here it's magnetic fillings that collects on magnets unlike bearings and pistons. So there's a chance to catch contaminants to stop collateral damages.
The culptit is the stock limited lubrication: low pressure thin oil over 10kMi. Cooling system damages in relation to extreme heatsoaks.
Rinse clean your oil filter bypass valve inside the plastic filter cover.
Also while in there... check for "oil in harness" at CPS, ECU and Lambda.
Investigate rattling loose VVT Gears for worned out lock pins.
Not to mention 2x new secondary chain tensioners.
(Keep injectors paired to their individually matched cylinder).
> REPAIR OR LET GO...
This may be viable to repair especially with free labor, parts only... nothing's impossible.
Before you start this whole repair... see if your new parts will be worth investing into this one particular chassis or cost higher than value.
Assess 722.9 tranny and suspension maintenance.
These cars are really well designed.
Last edited by CaliBenzDriver; May 4, 2025 at 10:58 AM.
I wonder how the camshaft 3x fuel pump lobes look like? (pump + roller + PCV kit)
Fine. no damage. Right lobes all look good.
Originally Posted by CaliBenzDriver
You found Bank2 extensive damages to both intake/exhaust camshafts nearest to oil supply side.
Yes both lobes on intake of cylinder #6 and just the front lobe on exhaust of cylinder #4
Originally Posted by CaliBenzDriver
if there's one good thing here it's magnetic fillings that collects on magnets unlike bearings and pistons. So there's a chance to catch contaminants to stop collateral damages.
The culptit is the stock limited lubrication: low pressure thin oil over 10kMi. Cooling system damages in relation to extreme heatsoaks.
Rinse clean your oil filter bypass valve inside the plastic filter cover.
I will check if I can.
Originally Posted by CaliBenzDriver
Also while in there... check for "oil in harness" at CPS, ECU and Lambda.
First thing I checked and the ECU had oil in part of one of the connectors (sorry do not have a wiring diagram it state which connect number). One of the CMP had some and the coil on cylinder # had a lot in it too. All cleaned with electrical cleaner
Originally Posted by CaliBenzDriver
Investigate rattling loose VVT Gears for worned out lock pins.
Not to mention 2x new secondary chain tensioners.
That was initial reason to for tear down. the left intake adjuster is bad and found the tensioner to be bad too. All ready have parts on hand. Check valve was already installed from factory per engine number and removing the tensioner yesterday.
Originally Posted by CaliBenzDriver
(Keep injectors paired to their individually matched cylinder).
Yes I did. I marked the coils too and the cam hold downs as well. I like putting stuff back in the same location even though "it doesn't matter"
Originally Posted by CaliBenzDriver
> REPAIR OR LET GO...
This may be viable to repair especially with free labor, parts only... nothing's impossible.
Before you start this whole repair... see if your new parts will be worth investing into this one particular chassis or cost higher than value.
Assess 722.9 tranny and suspension maintenance.
These cars are really well designed.
She bought it knowing the issue but the cam wear is a nice surprise. I can get a used intake cam with unknown mile with adjuster for $190 that I saw yesterday(will replace adjuster with new one I bought). Will it sold yesterday so that's off the table.
Or a whole used complete cylinder head without cover for $500 with 91k and replace the whole head or use just the cams from it.
I do not want to get a cheap china cam as I do not know the quality of them. The OEM ones might be made in the same factory if that is also from china but my guess is it is from somewhere in Europe.
Or I can just replace the adjuster and tensioner and just send it with the cam like that if the components under like ok.
Yes both lobes on intake of cylinder #6 and just the front lobe on exhaust of cylinder #4
I will check if I can.
First thing I checked and the ECU had oil in part of one of the connectors (sorry do not have a wiring diagram it state which connect number). One of the CMP had some and the coil on cylinder # had a lot in it too. All cleaned with electrical cleaner
That was initial reason to for tear down. the left intake adjuster is bad and found the tensioner to be bad too. All ready have parts on hand. Check valve was already installed from factory per engine number and removing the tensioner yesterday.
Yes I did. I marked the coils too and the cam hold downs as well. I like putting stuff back in the same location even though "it doesn't matter"
She bought it knowing the issue but the cam wear is a nice surprise. I can get a used intake cam with unknown mile with adjuster for $190 that I saw yesterday(will replace adjuster with new one I bought). Will it sold yesterday so that's off the table.
Or a whole used complete cylinder head without cover for $500 with 91k and replace the whole head or use just the cams from it.
I do not want to get a cheap china cam as I do not know the quality of them. The OEM ones might be made in the same factory if that is also from china but my guess is it is from somewhere in Europe.
Or I can just replace the adjuster and tensioner and just send it with the cam like that if the components under like ok.
You have this comprehensive repair methodically under control. Parts back to individual position
The ECU connector that feeds oil is named M. The second connector goes to chassis side.
I don't know how bank1 camshafts can be all good when bank2 is all gone.... prior repair?
Bank2 the most worned is the easiest function: most oil, least effort with HPFP yet is the most worned.
> CAUSE /FIX... Blocked oil passage ? or super leaky oil supply from loose tensioner seal + VVT dropping pressure.
Inspect the back plane of new tensioners. Polish using high grit 1000 sand paper on marble surface. Some leak straight from MB factory... mine new MB tensioners did.
Tensioners are mounted dry, the back plane better not be leaking.
> SHAVINGS... STRAINER!
The VVT mechanical oil control valve has a strainer filter - Be sure to clean!!
> COLLATERAL PARTS:
save your labor time...
Vacuum pump tiny check-valve
4x CPS + pigtails
HPFP + Roller
PCV kit (discharge conduite)
(spark plugs + boots)
??
Last edited by CaliBenzDriver; May 4, 2025 at 03:15 PM.
You have this comprehensive repair methodically under control. Parts back to individual position
The ECU connector that feeds oil is named M. The second connector goes to chassis side.
I don't know how bank1 camshafts can be all good when bank2 is all gone.... prior repair?
Bank2 the most worned is the easiest function: most oil, least effort with HPFP yet is the most worned.
No idea but I do not think it had a prior repair as I never inquired with dealer with VIN. I will call Monday. The HPFP is on bank 1 intake cam . So maybe typo on your part???
Originally Posted by CaliBenzDriver
> CAUSE /FIX... Blocked oil passage ? or super leaky oil supply from loose tensioner seal + VVT dropping pressure.
Inspect the back plane of new tensioners. Polish using high grit 1000 sand paper on marble surface. Some leak straight from MB factory... mine new MB tensioners did.
Tensioners are mounted dry, the back plane better not be leaking.
Good to know about polishing it but use glass as your flat surface as glass pours flatter but who has a glass sheet around
Originally Posted by CaliBenzDriver
> SHAVINGS... STRAINER!
The VVT mechanical oil control valve has a strainer filter - Be sure to clean!!
will do. going to have to inspect a lot of things now
Originally Posted by CaliBenzDriver
> COLLATERAL PARTS:
save your labor time...
Vacuum pump tiny check-valve
4x CPS + pigtails
HPFP + Roller
PCV kit (discharge conduite)
(spark plugs + boots)
??
One new CPS already. I will look at the others points.
Yes I know where HPFP is located... at 140kMi it's overdue.
You say your bank1 cams are both okay, right?
You know a flat roller is guaranteed to shave related lobes flat.
That's why I mentioned it to save your good Bank1 intake.
Also 1x CPS only is not advisable vs. 4x.pcs
The deal is you're either saving $50Ea. else you experience "$10k oil in harness" nightmare.
These are my tips towards your $10k savings
The opinion I don't have is how to decontaminate oil supply 100%.
Oil filter is partly in charge of cleaning oil. Pump solenoid may jam on low pressure.
Cleaning aftermath is part of this repair.
Last edited by CaliBenzDriver; May 4, 2025 at 05:32 PM.
Yes I know where HPFP is located... at 140kMi it's overdue.
You say your bank1 cams are both okay, right?
You know a flat roller is guaranteed to waste its camshaft lobes (ow fuel pressure)
That's why I mentioned it to save your Bank1 side.
yes with your extend knowledge i knew you know where it is just I miss understood it since bank 2 and the pump were mentioned on the same sentence.
yes bank 1 lobes and hpfp lobe are ok.
Yes a stuck roller will eat the crap the out of a lobe. The current hemis suffer from lobe eating lifter because of lack of lubrication because of long idle time.
Originally Posted by CaliBenzDriver
Also 1x CPS is not advisable vs. 4x.
The deal is ypu save $50Ea. else you experience "$10k oil in harness" nightmare.
Someone else just replace one before and I told them that wasn't going to fix that issue but he didn't listen.
And only one of the cps had oil in it (not a lot). It was tje replaced one and the car was not even run more then 30mins since replacing. Cars been sitting in the garage.
Originally Posted by CaliBenzDriver
These are my tips towards your $10k savings
The opinion I don't have is how to decontaminate oil supply 100%. Oil filter is partly in charge of cleaning oil. Pump solenoid may jam on low pressure. Cleaning is part of this repair.
guy changed the oil and filter think it would fix the start up noise issue. But never saved the old filter to look at it. I would have looked at it since it is a used car.
Thanks for help.
Buy some rare earth magnets (HF $2.99 regular price) and place them on the drain plug of course only if it is ferrous so they stick instead of a magnetic drain plug. I'm starting to do that and on the filter (canister style ones) just to experiment with. I pull some from an old harddrive.
You can experiment turning around limited lubrication by disabling oil pump MOD-1 plus upgrading stock oil that is essentially 0W-35.
My M276 runs extremely well on 5W-50 below 4500.Rpm.
Better pistons spraying will eventually help stop the extreme heatsoaks that toast head plastics (coils, CPS, Coolant lines, exchanger...) - Without pistons stored heat, there's no killer heatsoaks tank overboils.
The help I wrote earlier is to help stay ahead of troubles with couple maintenance tips.
And you can see the wear on the lobe as there is a pretty good shoulder easily felt with your finger not even needing the fingernail test.
And for reference for others, here is the reluctor spun on the cam by a lot. Was planning on turning the reluctor, drilling 2 1/8" holes and welding it in place.
these rollers need to go with their matching camshaft.
They clearly show uneven wear ready to chew replacement unevenly.
They are spinning with too much freeplay unparallel to cams profile.
The shifted reluctor is a really nice catch.
A lot of times there have NO laser marking to witness timing shift.
Exactly which reluctors have shifted:
both intakes B1+ B2 or
B2 intake only??
Last edited by CaliBenzDriver; May 5, 2025 at 06:47 PM.
@CaliBenzDriver i only removed the intake bank 2 cam as I had the adjuster loosen. Going to wait until I get the parts in to check the exhaust cam and then both bank 1 cams too.
Going to call the salvage yard about the $400 complete head and move the cams over from it. I guess I will order 4 new Febi Bilstein rockers at $11 a piece or should I source MB OEM or just transfer the matching ones from the used head?
Super impressed by your mechanic skills. I overthink things so my DIY projects that take 30 minutes (i'm not a technician, just an SA) I put off for 6+ months at a time because I overthink stuff. I always admire peoples ability to just dive in.
It looks like it could be chatter, If thats the case I think the camshafts have uneven loading on the caps from the factory due to tolerance issues, the cams want to push up and to either the right or left depending on which way they spin which could be what youre seeing I dunno I'm not a zoologist. TBH you could run it this way for a WHILE given your journals look okay-ish. I know that sounds stupid but I've seen some things. If you want to do things right though a new camshaft may not "solve" the issue the caps would need to be align honed. If you stuffed a new cam in there it might just do this all over again cept now youre out $550+,
@CaliBenzDriver i only removed the intake bank 2 cam as I had the adjuster loosen. Going to wait until I get the parts in to check the exhaust cam and then both bank 1 cams too.
Going to call the salvage yard about the $400 complete head and move the cams over from it. I guess I will order 4 new Febi Bilstein rockers at $11 a piece or should I source MB OEM or just transfer the matching ones from the used head?
If your salvage heads are good, transfer all rollers over to work with the same lobe.
Rollers that are not trashed are just a hair from it with loads of contaminants to chew on needle bearings.
If this is your own engine, try to prevent unnecessary duplicate work.
The shifted reluctor is caused by rattling being ignored ie. bad VVT.
If your salvage heads are good, transfer all rollers over to work with the same lobe.
Rollers that are not trashed are just a hair from it with loads of contaminants to chew on needle bearings.
If this is your own engine, try to prevent unnecessary duplicate work.
The shifted reluctor is caused by rattling being ignored ie. bad VVT.
I was typing before I was thinking. Yes good point about transferring all the rocker arms to matching lobes on the used cams and the eaten metal in all the needle bearing.
Yes the intake bank 2 had a bad VVT. I guess it shifts from the shock as the VVT snaps after you rotate the engine a couple of turns.
Super impressed by your mechanic skills. I overthink things so my DIY projects that take 30 minutes (i'm not a technician, just an SA) I put off for 6+ months at a time because I overthink stuff. I always admire peoples ability to just dive in.
Thanks but I am just a DIYer too. Sometimes I get up in the middle of the night going oh sh*t then I calm down.
Originally Posted by ChrisHimself
It looks like it could be chatter, If thats the case I think the camshafts have uneven loading on the caps from the factory due to tolerance issues, the cams want to push up and to either the right or left depending on which way they spin which could be what youre seeing I dunno I'm not a zoologist. TBH you could run it this way for a WHILE given your journals look okay-ish. I know that sounds stupid but I've seen some things. If you want to do things right though a new camshaft may not "solve" the issue the caps would need to be align honed. If you stuffed a new cam in there it might just do this all over again cept now youre out $550+,
There are no caps nor bearing on the journals, just the machined head and valve cover and looks like oil is squirted from the middle of lifers. There are 4 tie downs to the cams to the head but the bulk of the hold down of the cams are the valve covers (but someone can correct me). I am going to mic the journals. If honing was required, it would just be cheaper and better to install the whole head.
do not weld to cam shaft it is a very hard brittle material that does not take kindly to welding.
I think you original CAM was abused or defective and would hope any new one has fixed those issues.
I was going to just tack weld 2 spots that would not unharden it as not enough heat would be produced. Plus where I was going to weld it there was no contact with any support structure or any surface so even if it it unhardened the cam in that particular small radius of the weld it wouldn't be a big deal as the structural integrity of the cam would still be there.
But I know what you meant in term of metallurgy as heat unhardens hardened steel and if you do not pre heat you can get stress cracking form thermal shock, unharden the piece, etc.
I don't buy the "defective metal casting":
When you look at the wear pattern, evidence speaks differently.
1-- LOCATION :
The deep wear happen almost opposite of lobe on the lowest part of the profile: very little to no spring forces involved. Free rolling section!
2-- ASPECT :
It really precisely off centered to one side and like split over the center of the track.
Two very different patterns :
One side has deep pitting
the other side has smooth deep wear
This pattern shows the roller is exerting uneven forces over cam profile.
The camshaft can not shift side to create that pattern, only the roller can rock side to side.
This happen under "low tension".
3-- PARADOX:
Highly worned under low torsion !
This damage is from the raming of camshaft against loose VVT gear.
Under stock condition, limited oil pressure causes VVT lock pins to wear out loose. Without enough oil pressure the camshaft is able to roll forward and squeeze the oil out of VVT chambers to come and knock on full travel stop.
4-- LIMITED OIL PRESSURE :
-- During engine start, VVT are partly filled with aur such that if lock are defective, gear will travel unrestricted.
-- During low Rpm operation, VVT are filled with oil and very little to no air. Barely enough pressure to unlock.
Camshaft is able to rotate forward by squeezing low oil pressure from system.
What causes cam to rotate freely is springs forces against profile.
Not one set of springs but all those profiles that found worned out pushing together at one very specific spot when couple valve springs can push together.
This is how the rattle is created.
The wear is caused by worned out rollers forcing camshaft forward under low oil pressure condition.
Last edited by CaliBenzDriver; May 6, 2025 at 01:44 PM.
When you look at the wear pattern, evidence speaks differently.
1-- LOCATION :
The deep wear happen almost opposite of lobe on the lowest part of the profile: very little to no spring forces involved. Free rolling section!
The picture is not great so you cannot make out the profile.
The deep wear is on the high part of the lobe i.e. the nose of the lobe (lift section of the profile). the other sections (ramp, closing, base) are smooth no lip.
Originally Posted by CaliBenzDriver
2-- ASPECT :
Only intake of cylinder #6 lobes have shoulders. All others even the front lobe on exhaust of cylinder #4 that is pitted have no shoulder you can feel with your finger nail.
Single cylinder??
Your video shows 3 rollers... at least 2 Cyl , right?
Yes both intake cam lobe on cyl 6 high section
In the video, the first 2 rockers are the cyl 6 rockers
the 3rd one is cyl 5 rockers with the pitted lobe
4th is cyl 5 rocker with NO wear nor pitting
Going to buy a complete used head from a 116k mile 2760100813 Mercedes 2014 E350 W212. Cross referencing the numbers, the head numbers are different but the cams are the same. Scrap yard lists the head to work with the C300
Per the VIN, the E350 is: M - engine: 276952 30 684291 (276.952 M276 DE35, GASOLINE ENGINE V6 M276 DE35) and the C300 is: M - engine: 276957 30 490732 (276.957 M276 DE35, GASOLINE ENGINE V6 M276 DE35)
some of these M276 are 3.0L cylinder bores some are 3.5L others are NA, others are Turbos. Part number crossing is a necessary skill around MB products.
> Intake Cam pitting...
No6 on high lobe section
No5 ....
These Cyls. are away from oil pressure supply. Granted not as far as No3: surprise there?
That's consistent with high forces... dry lubed??
Last edited by CaliBenzDriver; May 6, 2025 at 07:16 PM.
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