I posted this as a reply earlier to another message but didnt get a reply so hoping to get some attention with a new thread. I have a 2013 c250 sport coupe with 114,000km. I had the rattling noise on start up, the hard starts and the engine warning light. So after much research decided the cam adjusters and timing chain needed replacing. It was a big job but both cam adjusters, the timing chain and tensioner were replaced. It started no problem after replacement and I cleared the engine warning light and everything sounded fine. Car drove without issue however 1500km later and everything is back to how it was before the repairs. Hard starts, rattle on start up and yesterday the engine light came on with the dreaded "cam" P0340 code. So has the chain stretched again....? Surely not!?? Any ideas... I dont want to be replacing the chain and cam adjusters every 2000km! I just changed the oil and filter trying all options now. I have gone from 5/40 to 10/40 but still the same thinking of going to a 0/40. The noise is only on start up once started engine is fine sounds nice and tight with no performance issues at all. So my thinking on the oil change was because the chain tensioner is oil pressure operated maybe a different viccosity would make a difference. Im kinda thinking a thinner oil like a 0/40 next as this would get the oil to the tensioner quicker....if thats the problem of course as the 10/40 hasnt helped!. Seriously throwing hands in the air at this point... How can I have replaced the parts and still have same issue. Oh and the weirdest thing is some times it starts beautifully no noise nothing, other days it sounds like someone has thrown a bunch of ball bearings into my engine and it cranks over for at least twice as long until it starts. Even if the tensioner is faulty this wouldnt affect the starting as the cams will still be held in the correct position by the chain (unless stretched) because the tensioner is on the side of the chain which doesnt affect the timing (and no it hasnt skipped a tooth I would be well aware if it had lol). Im even starting to think cam sensors, map sensor now etc etc....HELP!!!

 

Is the tip of the oil filter housing broken?

 

no dont think so, I had it off yesterday all seemed ok didnt notice anything broken or leaking... Are you thinking if its broken it would affect the oil pressure?

 

That sounding like a bunch of ball bearing rattle sure reminds me of when my timing was a bit off but intermittent nature is baffling. OEM replacement parts, right?

 

This scares me after having gone through this myself. Although mine went a little over 20K miles. I've now put about 30K miles on after the repair. I always use M1 0-W40.

I would think your repair should still covered but is sure sounds like cam adjusters.

 

OEM chain but not oem adjusters as mb adjusters are so expensive and obviously fail anyway so went for after market adjusters, So Michael71 are you saying you also did the repair and had the same issue after only 20k... or did it fail at 20k and since repair you have done 30k without issue..and does using the 0/40 oil seem better as I would imagine the thinner oil gets the pressure up quicker and gets to the tensioner quicker as well right? As for warranty its 100k or 3 years here in Australia mine has done 114,000km and is 4 years old lol! Im still thinking its more of a tensioner issue when it comes to the rattle sound at start up but cant explain the long crank time every now and again or the intimitant nature of the problem. Just for the record the past few days it has started without issue ( a little bit of a rattle on start up until the oil pressure activates the tensioner i think) but other than that all good so WTF!...? Positive th timig s spot on checked it 4 times ater repair (rotated engine back to TDC 4 times after repair and checked everything lined up which it did a bit of over kill but wanted to make sure everything was spot on.) It runs beautifully sounds great etc etc its just the start up that seems to be the issue and mainly when cold and/or warm (after sitting for an hour or so) if its starts when hot (normal running temp) its all good with no issues...weird I know....

 

Mine failed shortly after I purchased the car with around 20K miles. I've put about 30K miles on the car since and so far it hasn't come back.

I know all dealer services were done on time before I had the car. Since taking ownership I do my own oil changes and use the Mobile 1 0-W40 Euro formula.

I've heard that theory before on the oil weight. Hopefully the cam adjusters have been revised.

 

Note that a P0340 code is a generic code, meaning it is a common OBD-II code that applies to engines in a general sense. This is not the same as a manufacturer specific code, which may not be able to be read with a generic OBD-II scantool.

Also, the P0340 code specifically points to a problem with the camshaft position sensor circuit, not a problem with camshaft timing. In general, the position sensor is a coil of wire with a ferrous pole, pretty much the same as the crankshaft sensor and/or ABS sensors. It can fail as either shorted, partially shorted or open. In an intermittant failure it might miss the timing pulse once in a while.

The ECU can detect the sensor being open and/or missing timing pulses as they would be a consistent stream and directly proportional to engine speed. In any case, this code does not indicate a timing chain or camshaft timing problem, only that the position sensor circuit is not reacting as it should.

I've seen camshaft sensors and crankshaft ignition sensors go open or open when hot. In any case, I would suggest looking at the sensor or it's wiring back to the ECU as a possible cause, not the timing chain or associated components.

A lack of oil pressure at startup can result in a chain rattle until the pressure builds up. While I've not specifically looked the engine on the C250 in this regard, most engines that have variable camshaft timing have a locking pin on the pulley assembly which engages after the engine is shut off. If the pins acts up, you can get a rattle. It's a common occurrence on the Yamaha built 2ZZ-GE engine (used in the Lotus Elise/Exige).

 

Thanks floobydyst2 that makes me feel bit better and makes sense. I also may try the other suggestion as well and change the oil for a 5/40 or 0/40 to get the pressure up in the tensioner quicker. Interesting about those locking pins could also be an issue as suggested...🤔

 

Aftermarket cam gears?

I'd start with OEM gears and go from there. I've yet to see a set of the updated ones fail.

Correct oil filter right?

Oil thickness isn't really gonna matter on startup. You either have a check valve issue where the oil filter housing is not staying full and oil pressure takes too long to build, or the pins in the gears have slack and rattle on startup like what happened with your original gears.

 

That's good news! I seems many 2013 models had the issue.

 

Thanks guys, the only reason I went for after market gears was because the mb ones are prone to fail and cost $$$$. I hope it's not the gears... really don't want to have to do the job again... oem or not would the pins really wear after such a short time? I must say the engine does rattle a bit on some start ups and seems to be getting worse with the long crank time thrown in as well. Once running though it's fine.

 

The new part # gears don't fail in my experience.

 

And funny enough for the last two days every start has been perfect without fault... no rattle no and long crank....hope this continues... still confused this car is playing with me lol!

 

dont park the car, with the front facing downhill. The oil pump is in the back of the motor, so all the oil will be in the front, when you are facing downhill with the front. Instead, park your car level or facing uphill

 

With enough oil in the car, when the engine is off, the sump is full and the pickup tube is fully submerged no matter what angle the car is at. To think the car being at a slight angle is enough to starve the engine of oil, would be a severe engineering oversight.

The noise is from the gears not locking, they rattle until oil pressure builds up and then you don't hear it because they are full of oil.

New updated OEM gears will fix it. I have zero experience with the aftermarket gears, but i'd bet they aren't any better than the first design OEM ones.

Proper oil filter/oil quality is important, the bulletin requires us to check for fuel dilution of the oil and ensure an MB filter is installed before any work is done.

 

Thanks guys it's been a few days now and still all good... weird. If it starts again I may have to consider re doing the job with oem gears or this time just pay mb to do it! Fingers crossed...

 

 

Oh, I'm not an expert. I just had the issue myself and it seemed like there were many other reports of this occurring on here. Mine failed early on but the replacement held up just fine until I traded the car in.

 

Just a thought - as a quick and cheap check it might be worth checking the chain tensioner is installed tightly. It needs to be torqued to 40Nm - on the M271 EVO engines this is important as the tensioner is different to previous versions and uses a ratchet mechanism to keep pressure on the chain during cold starts before oil pressure builds. If it's not installed all the way in it doesn't keep oil pressure, and may not have released the ratchet mechanism either (you can check out You Tube videos on how this works and how to reset a used tensioner). If it's loose, you'll get a rattling like you describe and the chain won't be correctly tensioned.
Warning - if you take the tensioner out (or even loosen it slightly) once it's installed you can't reinstall it without resetting it (very easy to do, even easier if you use a bench vice to compress it after removing the ratchet pin).
PS. It's very unlikely the chain could have stretched again so quickly.

 

 

It's usually the gears/chain, not the sensors.

Are you using a good oil filter and correct oil?

 

Senor Italian Joe1

These timing chain tales - some at low odometer readings - are not helping my anxiety issues.

Would it be a fair statement that - given a low stress environment (easy use, CPO, oci at factory guidance et al - the majority of C250 1.8 turbos out there are without issues below 50,000 miles?

Appreciate any sage words to help me sleep.


all the best,



ez

 

It's hard for me to say how many of them have issues, as I mainly only see ones that are broken in the shop, good running ones just don't come in. It seems most of them are fine, and maintenance is key. I like the 271, and in general feel it's a more soild engine than the 270/274 but with any of these highly pushed turbo 4s, if you don't keep good oil in them you invite problems. Almost every one I've had with gear/chain issues is higher mileage and showing signs of sludge/lack of oil changes, yes. The early gears were problematic but I feel like most of them were caught and changed under warranty, we rarely see them now.

 

I'm pretty sure they tell you to check the oil for fuel contamination on the M271EVO because of the PCV system. I noticed that my oil was higher than max level one day and it smelled like gas. There is a PCV hose under the intake that goes from the crankcase to the intake manifold. That PCV valve was not only stuck, but the hose itself had a hole in it, so even some of my boost pressure came out of there ( the crack was on the intake side of the hose past the PCV valve ) . During the week or so that i had a stuck PCV valve, i noticed more chain rattle during startup. I did an oil change and it helped for a few days until the fuel got dilluted again. As soon as i fixed the problem
with a PCV hose, the chain rattle is gone. The stuck valve prevented many PCV gasses from escaping and unwashed fuel to settle in my oil. I probably had a liter of extra oil. I love my car, but the more i drive it, the more i realise that it's DESIGNED to break. Many of the things on it, are made of **** materials that make no sense to use.

So yes, i did notice more chain rattle with this PCV problem, which would have caused me to go get new gears and a chain much sooner than i need, if i didn't address this issue sooner. Also noticed more performance with the boost leak fixed.

Also you said it would be major design flaw for the oil to be not picked up at a certain angle. Well i guess it is a flaw since i noticed the difference in rattle the way i park my car.