mercyfan

In the morning on startup car now create rattle sound for 1-3 second. It needs timing chain service. Attached the in bottom audio record. I did research in youtube about that problem and two alternatives
1. Timing tensioner or oil check valve under tensioner
Mercedes Timing Chain Rattle Repair Kit - Genuine Mercedes 276050 | FCP Euro

2. Cam Adjuster most probably intake passenger side. This one can be tested by rotating crankshaft and see if it jump.

But based on mileage 180 k miles maybe I just replaced 1st both tensioner and oil check valve under it.
The timing kit from fcp had 16 aluminum bolts which cost around $97. Should I replace that aluminum oil to save cost?

CaliBenzDriver

You can save your cash if you can use only "2 finger tight" -or a screw driver to reassemble your camshaft front covers.

Consider the RTV sealant is really what's holding the covers, not the light aluminum screws.

Your engine will run smoother with tight stable timing. It's not just the noise, the camshaft timing is loose when VVT wobbles around.

Good luck 🤞

andynmaas

Agree that bolt is only torque to 8 nm and 8 of them hold one cover so it would ruin it.
The only tool I need is the press to push oil check valve as shown below which cost around $50 compare to mercedes around $280
6637 Inner Chain Check Valve Installer 276589003300 For Mercedes Benz SLI M276 | eBay

CaliBenzDriver

I wonder if you need the press tool or if you can hammer in these check valves gently using a spacer.

With your engine mileage, I bet the VVT lock-pins ate worned out regardless of oil check valves.

mercyfan

So do you think I should work on camshaft adjuster than timing tensionerin case alignment still ok.

CaliBenzDriver

I would start with replacing the 2x upper tensioners and check the freeplay in the VVT gears. Nowadays these are all wear items, with your mileage, it's no surprise to have worned out VVT.

I wish there was an upgrade path to a reliable RATCHETING tensioner instead of this simple spring with a leaky seal... ouch!
Having a tight chain tension gives a stable base camshaft timing. When the tensioner seal leaks too much pressure, the VVT low oil pressure causes lock-pin to wear out by locking in/out too frequently. Without a stable camshafts the engine shakes from different bank contributions.

andynmaas

This is my shopping list for 1st remediate of timing chain. Should I also replace all plastic part in that around that such guide rail or slide rail?.
Is it critical to fix the rattle asap to prevent more damage to timing chain are?

CaliBenzDriver

A -- your shopping car looks good if this is the right size valve diameter. The way MB plays it, they used two different bore holes and don't know engine No... The usual kit usually comes with both sizes.

B -- Personally I would leave both timing chains and guides untouched. Inspect the wear while you're inside timig cover.

C -- Lockpins rattle further damages. I think the No1 issue are metal particules roaming around passages. I don't think oil galleries have strainers that can get packed.

Arrie

When the rattle disappears that fast for me it tells the oil lines have drained and as soon as oil pressure comes back the rattle is gone. I would do just the check valves and see how it goes unless you just want to do the other parts of the job...

S-Prihadi

Sounds like VVT sprocket, my friend's M271 at 70,000KM was a tiny bit louder.



Since M271 is a 4 cylinder, so INLET and EXHAUST VVT sprocket , both oil control valve and tensioner.
Timing chain and plastic guide still good.

For ur 178K miles, I would do chain and all the plastic guide as well aside from all above mentioned for m271
Not cheap the parts alone...... use genuine one from MB

If you want to DIY, you can buy the camshaft locker bar and the special tool to remove the oil control valve. China made is good enough.
I already bought the tool...so cheap.
https://www.aliexpress.com/item/4001...80644010%21sea

mercyfan

The one most likely broken intake on passenger side. Maybe I should test and try that if that jump. I think it about $800 per cam adjuster and it used 4 of them
Many claimed it caused by bad oil and recommended one Liqui Moly instead mobil 1. Actually i just switch to liqui on last oil change and I also use liqui oil flush last time so maybe it affect that.

CaliBenzDriver

I think you are well on your way to getting this whole topic figured out... 👏

The passenger side VVT lock-pins and camshafts bearings tend to suffer from oil starvation caused by internal leaks through the original tensioners loose bore and weak seals. Replacement tensioners simply reduce leakeage with a normally tight gap.

When the oil has drained out from the heads through the conveniently missing check valve ports, you better have a good dry film like Ceratec to help while oil is coming up towards the camshafts rear - This old lubrication problem is a feature of V8/V6 engines that MB engineers perfected with managed oil pump output with normal/low pressures.

So I'd say cut this game short... replace leaky tensioners + add missing check valves sooner than later to lubricate passenger side camshafts rear bearings - Evidences learned from Master Tasos engine expertise.

Ultimately I think it's funny how well tolerated missing oil parts and defective tensioners are compared to discolored wood trims lawsuit - LOL

mercyfan

I found maybe three youtube show the problem of Left Intake CA became bad. So I think mine also had same problem but not jumping which make alignment bad and will trigger code about timing. It only make 1 or 2 second on some startup in morning.
I also found almost all Cam shaft and Cam Adjuster revised by Mercedes to resolve problem by searching part number in EPC. The CA even revised twice as you see below:


The good news the one we suspect good candidate is revised two times and the new revision is cheaper than the original but it back ordered must be everyone favorite and sell like candy.


The reason it cheaper it remanufactured because MB must get a lot of them replaced under warranty and they only replace the one it broken which is the bottom part and the lock pin plus spring (JHM sold only that part for Audi to fix CA). Below from mbpart.mbusa.com

The problem can we used that with original camshaft because all camshaft also revised.

mercyfan

It very interesting I found in youtube mechanic just repair cam adjuster instead of replacing it only welded the broken part.

mercyfan

This is the 2nd revised part based on EPC and it only cost $440 for 4 CA set
Maybe just buy this and just take bottom plate and the lock pin to reman the old CA

CaliBenzDriver

At nearly $100Ea. this looks like a great deal compared to $800Ea OEM.

As far as quality, the way MB builds them to fail, we might as well buy them straight from their China source

Do a quick quality control on each part before installing.

mercyfan

I found TSB for this rattle https://www.bing.com/ck/a?!&&p=089eb...E2NzI5Lw&ntb=1
but it only mentioned chain tensioner and oil check valve. The stranger thing there is 4 VVT but in all site FCP, Partgeek RM European, ECS one of VVT or camshaft Adjuster Intake left are out of stock. It will not that difficult to guess which part that I need to replace when that one of four VVT are out of stock.

Actually Mercedes had 4th revision of that part 2760505100 replacing 2760503600 but it cost around $1000. I did order from FCP chain tensioner and oil check valve. But still looking cam adjuster intake left. which the one made in germany cost around $200 are all out of stock. So maybe I just bought the one made in china in amazon or ebay.
I got result from Xentry Passthru using Tactrix Openport 2.0




I need help from expert here in forum which cam adjuster are the bad one.
Is that cylinder bank 2 mean cylinder on passenger or driver side?

CaliBenzDriver

In US LHD cars, it's the passenger side intake VVT that gets worned out first.

mercyfan

Thank you. I think bank 1 is based on steering wheel which mean for US driver side and bank 2 will be passenger side. I think based on EPC it called as Left Intake which based on we look from front of car.

S-Prihadi

Bank 1 is based on where cylinder 1 is, that is basic rule.
Avoid the term driver side or passenger side, it can confuse LHD/RHD car owners

M276
So bank 2 is LEFT of engine and Bank 1 is RIGHT side of engine. Seen from driver seat to hood or seen from flywheel/rear of engine

Sorry I can't access my WIS, but this will do, Arrow means front of engine
https://f01.justanswer.com/nmwagscha...ylinder_ID.pdf

mercyfan

If part called as left intake is that same left seen from driver seat?

S-Prihadi

Yes


===============
The DTC you got is based on an assumed healthy camshaft sensor.
It was a STORED code and not a CURRENT one, so don't jump to conclusion yet... it could be a cam sensor glitch.

The values of SPECIFIED camshaft degrees for Intake and Exhaust to what is read ( actual ) by sensor is only 2 degrees OFF and that is not DTC material yet.

There is a camshaft VVT/phasor commanded vs actual test Xentry can do, I forgot the name of the test. Do that test.
Attached is the test page



ADD : Use a minimum clean DC power supply/charger of 15Amps when using Xentry.
Low voltage can cause BAD/Wrong result. I see your battery voltage in the data freeze frame is 11.76V & 11.96V so low.

mercyfan

Thank for interpretation. I just had that Xentry Passthru 202106 running. I am struggle to install in my new laptop using windows 11 but finally i gave up and used my old laptop using windows 10 64 bit it work fine. That is my first scan and it really good because i thought there is no code. Look like from first incident it trigger that 7000 km ago.

S-Prihadi

me IT stupid and lucky Windows 10. I also chosen older Xentry passthru 2020 hoping it will be easier to run.
So far so good.

It will take time for you to play with Xentry if this is your very first time ever using it.
I have Autel to compare against, so at least I have a slight head start.

mercyfan

First I try 202206 and cant even store startkey. The key valid after disable secure boot in bios setup. But even it accept key it not working when i use it.
I still can not decide should i replace all 4 selenoid considering my car mileage 180 k miles