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I've been investigating an issue with my 2014 Mercedes Benz E350 4Matic, and I'm seeking advice from the community. Despite several months of research, I haven't been able to identify the root cause of the problem.
I've taken a closer look at the camshaft positions for both intake and exhaust, but the issue remains unclear. If anyone has experienced similar problems or has insights into camshaft-related issues, I'd greatly appreciate your input. Specifically, I'm curious to know if anyone has faced a situation where camshafts needed replacement for a facelift E350. Your experiences and advice would be invaluable. Thanks in advance for any assistance you can provide!
You have the standard rattling upon cold start. How to fix it?
What did your Xentry survey tell you is wrong?
> PART LIST involves these options:
Secondary chains tensioners
VVT gears intake/exhaust B1/2
Camshafts intake/exhaust B1/2
(CPS leaking sensors)
(HPFP roller)
(PCV Kit)
> Small rattles involves tensioners + CPS.
-- This is a great deal and simple repair.
> Medium rattles involve prior + Intake VVT gear B1.
-- This is a big step up as it requires valve cover removal ie. high pressure rail...
-- In that case replace HPFP, PCV parts as well.
> Large job involves all parts and both cam covers, injectors.
-- May NOT be worth doing: $$$$!!
> Live Testing:
You can forecast the repair job easily by looking at timing marks through the hole of CPS sensors.
From there you can see loose VVT skipping and you can see if cam reluctor wheels have shifted or not by comparing positions.
Concentrate all your testing efforts in Bank1 Intake camshaft.
Bank2 is not super affected and if it this damage survey will let you add up parts prior to commiting any repair.
> Low Pressure va. Lock pins!
One will argue the engine damages of VVT Gear lock pin are directly caused by low oil pressure. Frequent lock/unlock cycles while driving in city traffic wear out locks each idle and ECO stop...
>VVT Rattle effects :
The famous rattle is really caused by bank1 intake camshaft launching clockwise driven by pressure from valve rollers and HPFP lobes.
Most 4-strokes engines have this condition countered by good chain/belt tensioners. The non-ratcheting M276/8 hydraulic tensioners are not up to their task with low pressure.
Driving a high mileage engine with this rattle condition may be a viable option until the loose reluctor wheel gets shifted by the hammering. Then the ECU pulls timing codes. That's the step that makes camshaft work mandatory.
I've just found out our cars are somewhat related to the Freightliner tractor trailer company with the same owner.
These vehicles are well built to deliver a predictable experience.
Last edited by CaliBenzDriver; Dec 4, 2023 at 03:53 PM.
I think you got lucky No1 easy repair if this is a cold start. Rattle is pretty short and limited... NOT drawn like the VVT loose pin.
When fixing this you'll get a chance at testing VVT before reassembly.
Any mechanic may recommend VVT replacement... it comes around with mileage. Then ask for simple evidence of your VVT Gear being unlocked.
Last edited by CaliBenzDriver; Dec 5, 2023 at 03:39 AM.
I had cold start rattle last year, sounded like timing chain chatter. Happened around 7k into my last oil change. Had the oil changed shortly thereafter as routine maintenance and have not heard it since. Asked the shop about it, they said it’s sometimes a sign of needed oil. True or not, I haven’t a clue, but haven’t heard it ever since. Certainly not going to spend the money to fix it beyond that though.
I had cold start rattle last year, sounded like timing chain chatter. Happened around 7k into my last oil change. Had the oil changed shortly thereafter as routine maintenance and have not heard it since. Asked the shop about it, they said it’s sometimes a sign of needed oil. True or not, I haven’t a clue, but haven’t heard it ever since. Certainly not going to spend the money to fix it beyond that though.
this would be a case of low viscosity oil. Test have shown that 0W40 quickly become a W30 and these engines rely on good pressure to operate timing components.
You would do your engine a real favor by having new chain tensioners. Of course, nothing is mandatory.
Your startup rattle clearly says your tensioners bleed down because shaft seals are gone.
Jittery timing is associated with limp tensioners.
Now is the time to preserve your VVT Gears with best pressure. Some ppl advocate using a 15w50 in Florida summer (not Canadian winter).
Last edited by CaliBenzDriver; Dec 5, 2023 at 02:16 PM.
Attached is the most updated (that I have) version of the same TSB.
The TSB is slightly misleading us to believe rattle is caused by a missing check valve and early design of tensioners... Not so!
These are consequences, not causes.
This factory document is not about fixing the rattle issue thus I see it as misleading.
It's only amazing that a factory issued document sounds like the engineered issue is being investigated - Ouch! This extremely well designed to beging with.
-- TSB: "We forgot the valve and created a better tensioner... Everything good now."
--> This tensioner setup can rattle with check valves and new tensioners.
It does say right at the top "others causes not described in this LI..." - Likely related VVT Gears ignoring marginal oil pressure.
> Limp tensioners:
The fact is engines do rattle with existing check-valve and the updated tensioners.
The bottom line is these spring tensioners are the early source of rattles.
Good old ratcheting tensioners never go limp to rattle... that would be a serious $5 upgrade.
> LOOSE VVT lock pin:
Next major rattle is from worned VVT lock pin. This is caused by insufficient oil pressure forcing unnecessary lock cycles.
This is proven by pump solenoid experiment that restores engine torque near idle RPM. That says VVT Gear Intake Bank1 can NOT drive HPFP load with marginal pressure.
> Hydraulic Oil Pressure:
The only way to prevent rattle is by providing good working pressure to the timing components.
Anything that reduces oil pressure has negative impacts on engine basic performance.
Therefore you want:
good oil viscosity 10W40 (ie. W50!)
good non-leaking tensioners (40kMi)
good oil pump pressure
In 21st century, this is seriously basic. The hard part is connecting the dots through chaos. Now you have the complete TSB.
Last edited by CaliBenzDriver; Dec 5, 2023 at 03:55 PM.
this would be a case of low viscosity oil. Test have shown that 0W40 quickly become a W30 and these engines rely on good pressure to operate timing components.
You would do your engine a real favor by having new chain tensioners. Of course, nothing is mandatory.
Your startup rattle clearly says your tensioners bleed down because shaft seals are gone.
Jittery timing is associated with limp tensioners.
Now is the time to preserve your VVT Gears with best pressure. Some ppl advocate using a 15w50 in Florida summer (not Canadian winter).
Thanks Cali! No doubt you know what you’re talking about! This will have to be the burden of the next guy who owns it for me, I am ready to close the wallet and move on from the brand now. Planning on replacing mine in the spring for new Bronco. Mine will be 10 years old by then and probably around 85k gentle miles. As much as I love mine, it’s just never ending problems now. My highway humming noise within the driveline is back, shifting hard again, passenger seat split, brakes are pulsing again, and the pre-collision warning won’t go away. Just too much to deal with, calling Carvana and taking whatever they offer and moving on. Also curious how my wife likes the new Landcruiser next hear when it comes out. If she likes it, we’ll be exiting her 2020 GLS450 X167 too.
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