2012 Mercedes E350, 4,000 miles back I replaced one camshaft actuator and both banks chain tensioners while adding the anti drain back valves. Car was quiet after this work on start up. Runs great, good power, not one check engine event. The Timing Chain rattle is coming back on cold starts. I did read that some of the timing chain tensioners do not seal to the block well enough allowing this oil pressure bleed down?

Since my parts are new what would you guys do next? It is too nice of a car to rattle like a bad engine on start up. Now at 93,000 miles. Thanks

Mark

 

Mark,
you are right these cars should not have these common failures. New VVT + Tensioners then timing chaos rattle returned

Do you want to fix this easily for free ?

What oil are you running, a popular one?
How old oil ?
What color oil ?
Dipstick pic ?


oil color and viscosity

You changed one VVT gear, doesn't mean the other 3x are okay ✌️


I am saying you could have thin oil or bad bank2 VVT-Gear... same rattling result!

++++ Tensioner back....
you noticed the back has zero oil sealant and quite ruff.... sand it flat with 1000 grit 3M paper.
Make sure surface has no surface defects sticking out preventing best chance to seal.

 

Oil has less than 1,000 miles on it, Castrol, Euro 5-40W, previous change was only 4,000 miles back. It is not an oil issue. Your thoughts on the surface finish of the tensioner might have merit, it is losing oil pressure somewhere.
I know how to check the cam adjusters, my scan tool can watch them work and the engine computer checks for proper timing on every start up. I have heard the bad adjuster sounds it is more aggressive, louder, harder sounding.
This rattle is the fast, light rattle that quickly goes away with oil pressure, timing chain rattle.

I am convinced this is a oil pressure loss issue and the anti drain back devices are either not working or not the problem.

I might consider a film of the high tech silicone on the tensioner to help seal it. Just curious what others have done that actually solved this issue.

 

Why did you replace only one actuator? Was there an indication that only one needed replacement and which one?

 

Yep, with the covers off as you rotate the engine by hand you can see and feel the actuator Snap with each rotation. 3 rotated fine, never jumped, the broken 1 would jump and make the snap noise with every rotation. Seen this on other Mercedes engines also. Pretty clear which ones are good and bad.
Engine assembled cranking by hand you can hear it if you really pay attention but with the covers off you can both see and hear the actuator jump. I believe there is a YouTube video that shows this exact problem.

 

Recap:

1. 4x VVT are new or tested ok
2. not oil issue, fresh 5w40 in use
3. new tensioners + check valves

Then what else ???

You may be dealing with bad HPFP roller bearing giving a hard time to spin bank1 camshaft. This wasted your tiny VVT LOCK PIN!
Inspect HPFP and cam but do replace cheap old roller.

No need to pop valve covers. Injectors stay put!
How about that?

 

I can relate. Dealer replaced mine only for the rattle to return in short order, wasted $4000.

I have learned to mitigate to a degree. No short trips, that is no one to two mile trips, I have several cars so I would jockey them often, no more. I mainly use car for highway driving. And don’t let car sit for a week. Since then, rattling is all but gone.

Also I was using Molygen 5w-40 with Ceratec. I stopped using Ceratec at the advise of The Motor Oil Geek Lake Speed Jr. in an email. I am also monitoring my oil through oil analysis.

I’ve gotten a lot of good advise here. But the methods of how I use the car have show the best results for me so far. So, your mileage may vary.

Also a local Mercedes Master Tech of 25 years, says that the rattle is not harming the engine as the cam is limited in it’s movement, BUT, rare cases have shown over time can jar the camshaft reluctor out of place. But he said super rare. My OCD still obsessed over it.

What is happening, all the oil from the pickup tube to the oil filter is draining back into the sump overnight. The longer the car sits, the more oil drains into the sump. The longer the car sits, the more oil drains into the sump the longer it takes the oil pump to make full pressure after startup, and the weak springs behind the camshaft adjuster allows the lock pin to slip out, and then you have rattle.

The reason Mercedes rebuilt units act the same as your original, weak *** pin spring, and lack of oil check valve in the oil filter housing. Example, Chrysler integrated many Mercedes designs when they were owned by MB. The 3.6 oil filter system is identical to our engines, and a company has corrected their startup rattle by inventing an adapter for a conventional can filter, but more importantly a check valve to prevent oil from draining into the sump overnight and stopping all startup noises, not even a chain noise remains. No it will not fit our engines, and I wouldn’t use if it did, as no one makes a fleece can filter, and our cars require a fleece filter for the best filtering. But I mentioned it to help understand why our cars sometimes rattle when starting. Most never realize their car rattles, the quiet interior and most have their radio on when starting. I however, at cold start have door open, radio and a/c off, so I can monitor mine.

Hope this helps.

 

I had the HPP off of this engine and the roller for the pump looked and felt perfect, I see no reason to change a good part. I had to remove mine to change the breather vent or PCV due to oil in the intake manifold. I may consider making sure the tensioner is actually sealing against the block, that is one leak I did not consider when installing the new parts. I do not remember the surface being rough or being concerned about it.

 

Recap:

1. 4x VVT are new or tested ok
2. not oil issue, fresh 5w40 in use
3. new tensioners + check valves
4. HPFP + Roller tested fine

> Then what else ???
I would try a better engine oil before inspecting new tensioners back seal.

Can you capture a sound clip or two for us ?

We're going to help you get your luxury car rattle-free. It should not be a clunker.

 

I really like this car, just do not like the start up rattle, it is not the noisy sound you have with the broken cam adjusters. It is a fast pitched light rattle, sounds like the chain rattle. My sister in law used the car last week and starting it after sitting in her garage she heard the noise, ( knowledgable lady former race team member ) she knew it was not right and of course called me on it. Family pressure, I have to fix it now. I think it is a design flaw in this engine. Probably will not affect life of the engine but is just wrong.

 

the ratling is caused by the camshaft rushing forward. This royally de-tunes the engine exact timing.
The ECU doesn't have any great way to deal with random latencies of one bank of cylinders incidentally bank-1.

Normally the hydraulic tensioner oil has no way to escape. The one-way valve prevents draining down.
The seal on new tensioner front bearing-guide prevent oil from escaping when camshaft tries to squeeze tensioner.

 

I heard 5W-40 or better oil than Mobil1 solves or decreases the rattle issue. As long as it is not that infamous M276 rattle, then better engine oil will likely solve it or very least mitigate it.

You may also consider unplugging the oil pump solenoid, my cranking time decreased after doing so, more on it here, just read the FAQ, you don't have to do it if you are not comfortable: https://mbworld.org/forums/w212-amg/...solenoids.html

Edit:

Sorry about that, I forgot you already have 5W-40, in that case, depending if your place snow or not you might want to try 10W-40 but before that, do some research if 10W-40 is appropriate, you need specific MB certifications for your model.

I would recommend considering Motul, Pennzoil, Liqui Moly or even amsoil oils that are designed for your vehicle with the appropriate certifications.

 

Here's a radical thought, maybe the 50 petroleum engineers who wrote this actually know what they're talking about?

 

Thanks Pierre, guess I will get out the factory manual and read it. Our summer temps average a low of 65F and a high of 100F. Winter we rarely see 30F with highs of 50-60F. So maybe a 10W-40 is more appropriate. That would be an easy fix.

Working on the engine side of business we did find lifter failures sometimes when people increased viscosity in the engine. The roller lifers need thin oil to get into the roller needles. Other than that I see no reason not to change to thicker oil and try it.

 

A 10w40 is closer to providing the best cooling match for the engine.

'​​​​​​"Euro oils" with proper amount of friction modifiers seem limited to 0 or 5w40 viscosities.

Which off the shelves brand/product is that non-diesel, non-motorcycle, euro engine 10w40?

 

I will just verify the Mercedes SAE Spec and look for that. No other advertising gimmicks apply.

 

Mobil One makes it, I just ordered three five quart bottles for 81 dollars delivered including tax Amsoil,Liquid Moly, Shell and Castrol also make !0W-40 full synthetics.

 

the MB-229.5 spec will limit your choice to 0w40 or 5w40 "MB Approved" oils for stock engine conditions. Mobil-1 0w40 being the most ubiquitous oil for Summer/Winter.

 

They did lower the ash content slightly from 229.3 and 229.5

 

Well, it is an engine, nothing special, it is just an engine. I hate the rattle, I will try 10-40 synthetic and hope for an improvement. It does have Direct Injection so I am thinking a Dexos blend that is designed to help avoid intake valve build up will be my choice if it is available. Current oil only has 1,000 miles on it so I may wait a couple thousand more before the experiment. Thanks for all the input.

 

Where?

 

If worried about having a DI engine, you want API SP rated. If you are worried about carbon buildup, use a quality synthetic oil, drive more than a couple miles at a time, and change your oil every other week. (j/k). (Every 3000 miles)

 

No luck with Dexos, it does not look to be available in 10-40W. As an experiment I am leaning towards a full synthetic 20-50W oil, still reading up on them. My car is out of warranty so this is 100% on me if it works or not. Just looking for a quiet start.
My climate is on the warmer side so not really worried about a below 30F start, we don't have them.

 

You may not need 20W-50 to provide the much needed viscosity.

We can get exceptional results with a 10 or 15W-40. Not too much, not too little.✌️

The engine uses hydraulic pressure for VVT Gear and chain tensioners.
Viscosity is touchy. Going overboard is a bit counter productive.

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