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Discussion Starter #1
Can anyone opine on why the camshafts along with the cam adjuster would be replaced on a Metris?

I understand that some variants of the engine (c class I think) have/had faulty cam adjusters in the variable valve assembly which could starve the timing chain of lube.

Related? Stay away? Any thoughts or experience here is greatly appreciated.

Thank you!
 

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While starving a timing chain of oil is not a great thing, it’s not the most oil dependent of things on an engine, and intermittent starvation of oil to that part on its own would not likely cause you problems. Also most timing chains usually are lubricated by running it through the oil bath at the bottom of the engine, as well as oil in the valve cover.

your cams on the otherhand, need constant lubrication and are usually bathed in oil constantly as oil is usually bathing the entire cavity covered by the valve cover; that is why valve cover gasket leaks are so Prolific with oil.

faulty cam adjusters on the other hand are a major problem because they will cause improper timing in the combustion cycle, for reasons that have nothing to do with oil. Faulty variable timing adjustment gear has been a persistent problem for a variety of manufacturers since Honda invented the darn things. I have not heard of it being a problem on the M274/M270, or any other Mercedes actually.

Bad engine design is not a historic Mercedes issue. With the exception of the 4.7/5.5/6.3 DOHC V8s and the first generation aluminum V8s, both of which had timing chain sprocket problems, and the 3.5 I6 turbodiesel installed in certain 80’s and 90s S-class models, (they were essentially bored too big for their block) I have never really heard of Mercedes where the engine mechanicals are anywhere on the list of the vehicles weakpoints.
 

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As an aside and something to think about:
Don't forget that its not just chain that needs the oil, its their guides as well. On those GM (Isuzu truck engines 2.9/3.5) guides were wearing out because of oil passages getting clogged. Aside from noise, those multiple misfires will start to occur. Sure its on higher mileage engines, but still its important to prevent this issue when you know. It leads to engine rebuild. Where there is wear there is sludge.
 

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As an aside and something to think about:
Don't forget that its not just chain that needs the oil, its their guides as well. On those GM (Isuzu truck engines 2.9/3.5) guides were wearing out because of oil passages getting clogged. Aside from noise, those multiple misfires will start to occur. Sure its on higher mileage engines, but still its important to prevent this issue when you know. It leads to engine rebuild. Where there is wear there is sludge.
IMHO (and from experience) with Quality Synthetic Oil, there is No Clogged Passages and No Sludge, No Matter The Mileage
 

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IMHO (and from experience) with Quality Synthetic Oil, there is No Clogged Passages and No Sludge, No Matter The Mileage
I agree. The GM trucks I talked about didn't require full synthetic oil. Yet that was their biggest detriment. Most drivers will do the cheapest route possible to keep a vehicle, but pay in the long run. (oil type, fuel type, put off maintenance)
 
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