Originally Posted by Westlotorn

Follow up, I finally was able to get back to my 2012 E350 M276 repair. I pulled the manifold again and the cam sensors. Set the timing to 53* and checked all 4 cams. 3 were good but the bank 2 intake cam was slightly off center, no way it is a tooth off but the cam sensor pulse wheel was not spot on. I know they have been known to move and people buy new cams due to this failure. My cam adjuster is new, timing tensioner is new, oil check valve installed but this wheel is off. I took a 18” flat blade screwdriver/pry tool and moved the sensor wheel on the cam till it was lined up dead center as it should be looking through the inspection sensor hole.
It moved hard, took a lot of pressure but it did move. Have to be very careful, it takes so much pressure you can move it too far easily. Once I had moved this pulse wheel into position I reassembled the engine and fired it up. Right away the computer now sees the pulse wheel and the new cam adjuster on the bank 2 driver side intake cam started adjusting as it should. Check engine light is out. Engine now starts instantly, no delayed cranking and no start up rattle.

My thinking is that the failed adjuster and loose timing chain on start up hammers on this camshaft and the vibration makes the cam wheel slip out of position??? I have not heard of any cams being out of position without also having a failed Cam Adjuster or chain rattle at start up? There is no load on the pulse wheel so I suspect my wheel will continue to work properly as long as the Cam Adjuster and chain tensioner work properly with no start up rattle. I hope I am correct this was a 2 hour fix start to finish without removing the Valve cover or front timing cover. Engine runs like a top, quiet and instant start up so it feels like it worked. If my pulse wheel had moved easily I would have gone for a new cam but it was difficult to get to move. I think it is good.

My Scan tool shows all 4 cam adjusters now working and adjusting properly, before this repair the bank 2 intake cam adjuster would not adjust and was stuck in one position. My scan tool told me the cam was out of position and could not function until proper position was achieved. I was thinking I messed up and the timing was 1 tooth off.

Update tonight: Was able to take this car on a 50 mile drive, first 25 miles were mostly uphill with several steep grades, the engine pulled really well, better for sure than before the repair. I had purchased this car broken so I never felt it run at 100%. I set the cruise control at 74 headed up the hills. It held 74 without downshifting running close to 2,000 RPM. I was impressed. Power is very good. I took it to redline twice just to see how it sounded and if that caused any issues. All Good. I think this is a good runner now, it actually sounds like a good Mercedes engine instead of the rattle trap, slow starting beast it was before. I appreciate the tips the forum offered along the way. If the pulse wheel moves on me in the future I will certainly report back. All Good for now and I am happy.

Originally Posted by Westlotorn

I am struggling with another E350 right now, a 2013 that has a misfire in #1 cylinder. I am just hard headed and keep at it till I find solutions. To fix what you are looking at you will be pulling the valve cover off. Watch the YouTube videos on this it will save you time. Also before removing the camshaft clean and mark the sprockets, chain and the crank pulley so you know exactly where they go on install. I also put a small dab of paint, (white out works well) on the cam adjuster bolt and on the cam adjuster just beside this bolt so you can see that the adjuster is not moving as you rotate the engine.
I just removed and replaced a camshaft yesterday so this is fresh for me. With the cam cover off I rotated the engine by hand as I watched all the valve positions. I was looking to find a spot where the cams were not compressing the valves open. I found what I thought was the best spot, in this spot the timing chain adjuster was also at its most extended position which means when you remove it you will have the most amount of chain slack, on install from this position the tensioner can go back in with no effort at all due to this available slack. This is an eyeball thing, watch the cam lobes and watch the tensioner. My TDC mark on the crankshaft was nearly straight down in this spot I chose to use. Now in this position mark your camshafts. Mark the chain clearly to the exact spot lining up with one tooth on the sprockets, Mark the cams so you know where they line up to the top of the head on each side. This is not a guessing game, timing has to be exact or you will be doing this over again to fix it,. Before you glue down your valve cover test install it and install all bolts carefully to bring the cam all the way into position. With these bolts tight now rotate your engine and verify your timing marks through the windows at the cam position sensor holes. The timing will be off just a little on this side of the engine because the tensioner is not full of oil and pressurized but it will be close to perfect. I am sure I missed some steps. You also need to know that the cams will not fall back into the perfect spot and allow you to bolt it back in. You will be moving the cams a little and the crank a little to get all your marks lined up, just make sure you keep tension on the timing chain so it does not jump timing down low in the engine or you will be out of luck. You can hold it tight with your fingers while you slightly rotate the crankshaft to align on install. I also snap a vice grip tool on the cams to hold them where I want them. There is a spot you can use near the center of the cam that is open and is not a bearing surface to do this. This is a complex job and needs to be perfect or you pay a price so study up and don’t trust my notes, I may have forgot to mention something important.

Originally Posted by GLKwanter

Thanks for the reply. You're marking ideas I've noted, and are brilliant. You know though, I've seen enough videos that I don't think you have to remove the intake or valve cover to get the adjuster out through the timing cover.
https://youtu.be/dVFfIcrQfus
https://youtu.be/frSl7MZDhB8
I was going to start by removing the driver side timing cover and inspecting the intake adjuster by rotating the engine by hand and seeing if it jumps or pukes oil like so many do when bad.
I'll have the tensioner check valve and the adjuster for the driver side ready to install. I figure if I'm in there best to do everything so I don't have to spend $70 on another set of bolts.

Originally Posted by juanmor40

How do you verify this plate is in the correct position respect to the camshaft w/o taking off the valve covers? I thought the laser marking was in the back.

Originally Posted by Jaybird123

GLK...are you driving a GLK or a 207? Only asking since that driver side timing plate removal is a LOT harder on coupes like mine, as you have to remove the oil filter housing to do so...and that leads to a cascade of other part removal/replacements

Originally Posted by GLKwanter

2013 GLK 350. I've been reading every thread about the rattle

Originally Posted by juanmor40

Is your engine within the serial numbers that require either chain tensioner, or check valve? The 2012 ML is within the range, it has never had the rattle (knock on wood), it has been with my sister since it had 36K+ miles, and it is about 120K+ now. We have no record of the chain tensioners, nor check valve ever done on it. It had a camshaft sensor code once (forgot the code, but @100K) on bank 1, the sensor was replaced, and so far running smoothly.

When the rattle starts, the damage has been done to the adjusters. If caught early in the rattling, the check valve will protect it from further damage but its life expectancy has already been compromised. If the rattle is not addressed, the adjuster will deteriorate faster and it can suddenly lose timing if the back plate slips on the camshaft.

Currently, I look after 3 M276 engines, and they are under a strict diet of 5K miles of oil changes and moved them to 5W 40 MB approved oil (recommendation from my Indy, and several forum members). Unfortunately, we followed the 70K miles oil transmission MB's recommendation, but moved to 50K miles for the 2012 ML, and so will be the next ones for the 2014 E, and 2015 ML.

Originally Posted by Westlotorn

I have seen the one hour cam adjuster video, I tried ti twice now and failed on both times. The cam moves to a position where the valve springs push it. When you release the tensioner the cam may jump 5 teeth. Hard to recover from that. The guide above the chain in the valve cover also snaps when the chain jumps so you are pulling the valve cover regardless to fix that.

I do not think you will be able to fix the camshaft sensor wheel without removing the valve cover but if you do please post we all need to learn better ways.

Originally Posted by GLKwanter

Yes my engine is within this serial numbers that requires a check valve and new tensioner. From the Carfax I don't believe the engines ever been cracked open in the 135k on it. I see the transmission was serviced at 92k, I'm going to do it again right after I get rid of the rattle, what would you put in? Good service history very regular oil changes. I bought it a thousand miles ago. Dealer hid the startup rattle on me. No warranty. I'm just going to take care of it. I can do it better I've changed the oil, with Mobile 1 European full synthetic ow-40. Even though the history reports said it had been done 3K ago. What I put in looked a little cleaner. What's the added benefit of 5W 40? I'm in the Southwest heat a lot of stop and go city, but only 6K miles a year. Thanks for that info on the rattles damage, it checks with everything I've read and seen. That's why I just went right ahead and bought the adjuster along with the tensioner and check valve.

Originally Posted by Jaybird123

Interesting re 5W40, I'm still on the M1 0W-40 path currently but will research that further!

GLK, I am now envious of non-turbo engine owners lol. You should have little difficulty with the tensioners and sensors on either side. Those were really among the easiest steps of my recent overhaul. Cam adjuster was a good bit more difficult given valve cover removal requirement.

@juanmor40 I am now trying to discern the root cause of my new p001685 code following cam tensioner/sensor/B1 intake adjuster replacement...any thoughts? I will make a separate post shortly...I also have delayed startup and my Eco light does not turn on by default (which would be great if not a symptom of a bigger problem lol)

Originally Posted by GLKwanter

Camshaft sensor wheel? Is that the adjuster sprocket? The camshaft position sensor I don't believe to be malfunctioning on my vehicle. I just have the rattle, therefore need the check valve tensioner and probably adjuster.
I haven't heard anyone speak of replacing the guide above the chain. I am in a GLK350 2013 just for clarification not sure if that makes a difference.


Edit:
Wouldn't the timing chain need to be removed for the camshaft adjuster to move when the tensioner has slack and is removed? I haven't seen anyone complain of camshaft movement... Hmm
That sounds silly now that I read it. I know you know what you're talking about. I doubt I'll be able to show anything new I'm just hoping to eliminate the rattle.

Originally Posted by juanmor40

Here is how the camshaft is replaced w/o taking the timing chain off. I am not sure I will take the risk this mechanic took, i.e. I would have some strong string/wire/rope around the chain so it is always tense and does not miss a tooth just because I stumble on something (avoid before regretting)

https://www.youtube.com/watch?v=mAk_QSfFRmI

Originally Posted by juanmor40

From what I read in the past, with no personal experience, that code is hinting towards my first question here: how do you check if the plate (reluctor/tone ring) behind the camshaft adjuster has not slipped because of the rattling? The plate is
https://cimg3.ibsrv.net/gimg/www.mbw...17f2b4db14.png
As you can see in the picture (from a used part of Ebay), the plate is pressed on the camshaft; therefore, it can slip if the torque is "the right one" or because of a persistent vibration, i.e. rattle.

Here is a snapshot taken from a video about the M274 engine, same type of camshaft. Notice the arrow are pointing to the same relative position of the shaft, and see how far away/different is the position of the reluctor wheel . I bet that engine did not even start.

https://cimg4.ibsrv.net/gimg/www.mbw...b5bae3112a.png


If the plate (whatever its name is) already slipped, the ECU will compensate as much as it can but it will trigger an error at some point. That error can be p001685. How do you know?
1 - Swap sensors between intake bank 1 to intake bank 2 --> Did the code move to bank 2? No -> Problem is not the sensor
2 - Swap solenoids between intake bank 1 to intake bank 2 -> Did the code move to bank 2? No -> Problem is not the solenoid
3 - Here is more difficult: adjuster or slipped plate? You know the adjuster test process, correct? Did it pass, i.e. did not jump when rotating the engine manually? If so, the plate has slipped.
4 - Say the adjuster failed, and it is replaced. Did test 3 say anything about the plate slipping? Only if the adjuster did NOT fail. if the adjuster failed, the plate's correct positioning must be checked visually; otherwise, you risk putting everything together and getting the code again, , and need to reopen to do it anyways. Your call at that point
5 - you open the valve covers and visually inspect the plate positioning, and it fails (there is a tool to check that). New camshaft is the MB standard procedure ( https://mbworld.org/forums/c-class-w...ml#post8457971); however, others have been creative to realign them. How creative can we/humans be? A lot: @Westlotorn just did it a few weeks ago, and here another one (https://www.benzworld.org/threads/p0...crank.3112839/ )

My 2 cents.

here is a video about what I talked about
https://www.youtube.com/watch?v=oE1oNZI5mss

Originally Posted by Westlotorn

As you take the adjuster wheel off, providing the valve cover is removed it is simple to hold the timing chain so it does not slip down below. I have even taken it and rested it on the camshaft with the cam adjuster removed. You just do not want it to fall down into the engine, I know it could not go far down but the slack can cause you troubles. The last couple times I took a light duty bungy cord and hooked the chain and hooked to to the engine with just enough tension to keep the chain from falling inside. The etch on the cam adjuster and the camshaft is very hard to find and see. There are two marks about 3/8" long each and they need to match up exactly, I mean Dead straight on. Any variance can give you camshaft trouble codes. The car I just finished had 3 of the 4 cam sensor wheels out of alignment.

Originally Posted by hashim1995

tensioners torque specs was 9Nm, front cover was 5Nm and you have to replace bolts because they become very brittle but you can get away with it by tightening them very careful.

Originally Posted by Adrenalinaddict

Sorry to dredge up an old thread. I just did my timing chain tensioners and torqued them to 9nm. But it seemed really light and now I'm paranoid they will back out. I used new hardware as previously advised

Originally Posted by JCM_MB

I know, but if you torque them a bit more, they WILL snap in two. They are aluminium bolts.

In case you think it's a typo, here is the original document posted in another thread,

https://mbworld.org/forums/attachmen...743d1615087556