engine rattles on cold start .. Is it time to replace the Timing chain??

[sam3003]

Hi there,

For the last year or so, I have been having a rattle when the engine started for a few seconds and then it went back to normal till the following morning.

This happens mostly in the morning on a cold start on my Mercedes c200 (160k mileage).

MB dealer noted : (extreme nosiy timing chair on start) in the Visual Health Check mid of last year.

When I took it to the indei and left it overnight for another issue, he said that the car started fine with no rattle. He however advised me to get it check if the rattle happens often/ or for a longer time.

I have read other posts for the same issue and one of the comments was: ((Change tensioner first, relatively easy job can be done with engine in situ. They are a bit of a weak point on these engines.
If noise still there, then chain can be changed once again with engine in situ. However, if the chain is badly worn then the chances are three sprockets will need replacing too.
The two camshaft sprockets are changeable with engine in place, but the third crank sprocket can only be changed with engine out ))

Do I need to insist on the indie to check the car again?
I am worried I might damage more parts which will cost me more to replace.

Another question please, is it true that it is better not to use the stop/start function as this kills the timing chain??


Thanks

 

[Smiley]

You are right to be concerned. A noisy chain and 160k miles - presumably on a om651 engine? - is asking for trouble if not sorted. If it lets go then it is not just a "few more parts", you will most likely be needing a new engine and that is a whole different world of pita and ££££ to source and fix.
How good is the indi you use? Is it a proper Mercedes indi with a good reputation - if it is then I would go with their recommendation and erring on the side of caution due to the downside risks - if it i not a proper mercedes indi then I would be finding one quickly and get their opinion.

 

[Smiley]

The stop start thing might be good for the environment but it is less friendly to your wallet.....more wear on the starter motor, alternator, battery and yes I guess the timing chain as well.

 

[sam3003]

You are right to be concerned. A noisy chain and 160k miles - presumably on a om651 engine? - is asking for trouble if not sorted. If it lets go then it is not just a "few more parts", you will most likely be needing a new engine and that is a whole different world of pita and ££££ to source and fix.
How good is the indi you use? Is it a proper Mercedes indi with a good reputation - if it is then I would go with their recommendation and erring on the side of caution due to the downside risks - if it i not a proper mercedes indi then I would be finding one quickly and get their opinion.

Sorry I am not so technical but the car I have it a 2.1 C220 BlueTEC Sport G-Tronic+ Euro 6 2014 which I bought from MB as an approved used (60K) and I did not get any documents with it as to the parts which were replaced in the past. The indie was recommended to me by a taxi driver when I complained to him about how bad MB dealer were. The indie google reviews were good so I gave it a go. Aprt from the rattle, can the problem be diagnosed visaully by the indie? What parts should I tell him to check? thanks

 

[FlorinM]

Hi Sam,

The urgency of this issue really depends on how long you can hear the rattle. With that said at this mileage I would be on the side of caution and replace the tensioner.

A new genuine tensioner is £100 + labor to fit, which is a lot cheaper than changing the chain itself which is usually over £1000.

If the new tensioner doesn't solve the rattling then consider yourself lucky that you identified the problem early enough and maybe it won't be an engine out job.

Looking forward to hearing back from you!

 

[markjay]

Firstly, some rattle at cold startup is normal and it could be either the timing chain (typically because the hydraulic chain tensioner isn't tightening the chain properly until the oil pressure builds up), or the hydraulic tappets (they will rattle until the oil pressure builds up).

You suspect an issue with the timing chain because the MB dealer told you that (a) the rattle was excessive, and (b) it came from the chain.

But then your indie said that everything was normal.

Personally, on a 160,000 miles car, I would err on the side of caution and get the cam cover removed and the chain, guide, tensioner, and sprockets inspected and parts renewed as needed.

But then the question is - how long do you intend to keep the car? It might not be worth the bother if you are not planning on keeping it for much longer. On another note, have you had any issues with the AdBlue system?

 

[sam3003]

Firstly, some rattle at cold startup is normal and it could be either the timing chain (typically because the hydraulic chain tensioner isn't tightening the chain properly until the oil pressure builds up), or the hydraulic tappets (they will rattle until the oil pressure builds up).

You suspect an issue with the timing chain because the MB dealer told you that (a) the rattle was excessive, and (b) it came from the chain.

But then your indie said that everything was normal.

Personally, on a 160,000 miles car, I would err on the side of caution and get the cam cover removed and the chain, guide, tensioner, and sprockets inspected and parts renewed as needed.

But then the question is - how long do you intend to keep the car? It might not be worth the bother if you are not planning on keeping it for much longer. On another note, have you had any issues with the AdBlue system?

This was very informative, thanks

Yes I did have and still have a major issue with EML because of adblue system. The indie replaced the pump recently but the EML came on again. I was told that another examination was needed for an issue with the exhaust system. before this I had the nox sensors replaced back in 2021 under warranty

 

[markjay]

Oh, yes, just realised I replied to your other thread.

The reason for asking is that if the car has AdBlue issues, then personally I wouldn't invest too much in it.... I'd get it sorted so that the EML is off then trade it in before the EML comes back - sorry if this is not what you wanted to hear...

 

[Smiley]

Post number 8 is excellent advice.
Ad blue and timing chain problems could easily be a large four figure bill.
Until MB make a better job of looking after the owners of the unreliable adblue equipped cars, I can't see why anyone would buy one.

 

[Tonygw]

A timing chain and tensioner is around £700 at a good indie, its a known weak spot on the om651 but really isn't the end of the world compared to some cars issues.
At 160K miles its due anyway, an older belt driven engine would have had two timing belts by 160K and probably cost more. Get it replaced and drive happy.

The cheapest car to buy is the one you own..
Getting another car doesn't cure the problem unless you can 100% guarantee the new car wont have issues, and since every car I have ever owned has had wheels (and anything with wheels will cost you £££) then I would get it fixed.

 

[Smiley]

A timing chain and tensioner is around £700 at a good indie, its a known weak spot on the om651 but really isn't the end of the world compared to some cars issues.
At 160K miles its due anyway, an older belt driven engine would have had two timing belts by 160K and probably cost more. Get it replaced and drive happy.

The cheapest car to buy is the one you own..
Getting another car doesn't cure the problem unless you can 100% guarantee the new car wont have issues, and since every car I have ever owned has had wheels (and anything with wheels will cost you £££) then I would get it fixed.

To a large degree I would agree with you - but with some cars at certain mileages and with half known or known faults there is also a sensible time to jump ship.
If had a 160k mile euro 6 om651 in which I had already done 100k miles without too much expenditure then I would definitely be selling the car - and it is the adblue expense and pita hassle that would swing it for me - it is just not worth the £2k (on top of all of the other maintenance expense on that sort of mileage car) that it is going to cost over the next 40 or 50k miles. Get rid of it and buy something other than an adblue diesel.

 

[Smiley]

I suppose there is another option - replace the chain and map the adblue system out. I know it is illegal and you might get caught but unlikely in reality. And then just run the car into the ground.

 

[Tonygw]

Yeah its always that difficult balancing act with cars.. at what point do you quit? Nobody wants a money pit, and cars these days seem to be built to be money pits LOL

Although I can imagine the OP selling it only for the new owner to appear on here soon after asking for help with the same faults.. LOL

Cars..

 

[markjay]

Yeah its always that difficult balancing act with cars.. at what point do you quit? Nobody wants a money pit, and cars these days seem to be built to be money pits LOL

Although I can imagine the OP selling it only for the new owner to appear on here soon after asking for help with the same faults.. LOL

Cars..

The obvious issue is that the best time to advertise a car for sale is when it has no faults, but then you're reluctant to sell it because you think you've finally got it fixed.... then when it breaks down again you want to sell it, but can't, untill you fix it... and so it goes.

 

[Petrol Pete]

AdBlue is German for SELL IT NOW !

 

[sam3003]

To a large degree I would agree with you - but with some cars at certain mileages and with half known or known faults there is also a sensible time to jump ship.
If had a 160k mile euro 6 om651 in which I had already done 100k miles without too much expenditure then I would definitely be selling the car - and it is the adblue expense and pita hassle that would swing it for me - it is just not worth the £2k (on top of all of the other maintenance expense on that sort of mileage car) that it is going to cost over the next 40 or 50k miles. Get rid of it and buy something other than an adblue diesel.

Because of my annual high mileage, I feel that if I sell the car now and buy another one under 50k mileage I might have other major issues unless I get the MB warranty for £££ a year and MB service then sell the car before it hits 100k in two or three years. Moreover, I could not find any MB petrol car that is euro 6. On the other hand, if I replaced several adblue parts, I will get the MB 2 year part warranty for some peace of mind. Are there any other major parts I might to be worried about replacing soon?

 

[markjay]

...I could not find any MB petrol car that is euro 6...

I am assuming that what you are trying to say is that it is difficult to find second-hand petrol cars? Because all petrol cars (including MB) sold in the UK after 2003 are Euro6.

 

[sam3003]

I am assuming that what you are trying to say is that it is difficult to find second-hand petrol cars? Because all petrol cars (including MB) sold in the UK after 2003 are Euro6.

I must have misunderstood the LEZ requirements then. I thought the car needed to emit less that 110g/km.

What E class petrol MB car do you recommend for motorway with good mileage please? Thanks

 

[Smiley]

If I were in your position of having to get rid of my car because of the maker's poor product and pricing policy for spare parts I would not be buying another one.
I would be looking at BMW or one of the Japanese or possibly Korean brands for a petrol car.

 

[DITTRICH]

The ULEZ operates on EUR4 Nox limit (NOx emissions of 0.08g/km) for petrol cars. Some MBs meet the EUR4 Nox limits EVEN THOUGH THEY ARE NOT EUR4. As inferred, the general guidelines published do not "work".