Cold engine tapping noise

[Tonygw]

Hi Guys

2012 C250cdi estate with the OM651 currently on 116K miles with full service history

Noticed when cold (outside temp 10C or lower) the engine makes a tappet noise for 5-10 seconds when started from cold. A quick blip of the throttle and it goes away.
Had the chain and tensioner done at 90K so don think thats at fault.


Last oil change was 110K so probably due a change.

Any ideas what it could be, Could it be a noisy tappet or a failing injector? Or something else?

Thanks

 

[Tonygw]

This isnt mine but this is what it sounds like

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[Notamech]

I noticed the same on mine these past few days, ever since temperatures have started to fall. Didn't have this all summer also overall NVH seems higher on the first start on a cold morning its fine afterwards even if i start it again in in the evening if the engine is cold again it doesnt sound as bad as it does on a cold morning. And my oil was changed ~1000 - 1500 miles ago

 

[markjay]

Without listening to the noise it is difficult to say, but some clatter when cold, i.e. until the oil pressure builds-up inside the hydraulic tappets, is normal.

 

[Tonygw]

Thanks chaps, I think it is tappet noise but it's difficult to know for sure. Doesn't sound like chain noise as that's more of a clack clack clack noise. As mentioned its only first thing in the morning. During the summer is was very quiet. Now it's colder I guess the oils a bit thicker so takes longer to circulate. Wonder if a new oil filter will improve things.

 

[StMarks]

My first Vito (a 638 110cdi) had a "similar sound" when I purchased it.
I expected it would be a tappet, so brought it fully aware of the fault (cheap).
In my instance, the sound didn't go away once warm (although the vendor did inform me that it had been making the noise for "ages", and that when it began "it was only when it first started"). He also pointed out that it didn't seem to effect it's performance.
It wasn't a tappet, & took me a while to identify the fault.
My tapping turned out to be piston slap.
I identified the damaged piston, replaced it and it ran witout any tapping after that.

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[Tonygw]

Glad you sorted it, the noise is much louder than mine. After it starts it goes within a few seconds and doesn't appear again until the next morning. Even if I start it cold later on in the day. I'll keep and eye on it for now. At 116k miles I'm hoping it's nothing serious, car has a full service history with regular oil and filter changes.

 

[Notamech]

Glad you sorted it, the noise is much louder than mine. After it starts it goes within a few seconds and doesn't appear again until the next morning. Even if I start it cold later on in the day. I'll keep and eye on it for now. At 116k miles I'm hoping it's nothing serious, car has a full service history with regular oil and filter changes.

Like i mentioned i have this too. Researching more on this apparently its normal. Theres this metal pipe attached to the turbo you can see it just under the plastic intake pipe. The pipe has a thing in it that rattles. You can get it sorted but unless youre good at DIY it might cost a fair bit. See below videos.

The pipe

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The thing

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[Notamech]

Also here is what mine sounds like. I have the rattle for sure plus i think one of my injector / tappet is knocking as well

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[Tonygw]

Ah ! thanks for the videos, always useful to hear other peoples and compare.
Sounds very similar to mine. I wonder if it is this the part in the turbo tapping. If it is an oil change on mine, which is happening next week, won't make the slightest bit of difference. LOL
I did also wonder if the injector might have a slight leak when cold causing a tap noise? was going to check but haven't had time yet. I did have the chain and tensioner replaced at 90K so I know all the injectors have been removed and refitted,

Incidentally, what mileage is yours on and does it have a good service record?

Im just passed the 116K miles which is still considered low/average for these engines. Was hoping to get it up to closer to 200K and beyond before I retire the car. So a few years to go yet! I have a full-service history but early on in its life it was on the Merc extended servicing at 18K miles which is way to long for a modern diesel engine.


Cheers

 

[Notamech]

Ah ! thanks for the videos, always useful to hear other peoples and compare.
Sounds very similar to mine. I wonder if it is this the part in the turbo tapping. If it is an oil change on mine, which is happening next week, won't make the slightest bit of difference. LOL
I did also wonder if the injector might have a slight leak when cold causing a tap noise? was going to check but haven't had time yet. I did have the chain and tensioner replaced at 90K so I know all the injectors have been removed and refitted,

Incidentally, what mileage is yours on and does it have a good service record?

Im just passed the 116K miles which is still considered low/average for these engines. Was hoping to get it up to closer to 200K and beyond before I retire the car. So a few years to go yet! I have a full-service history but early on in its life it was on the Merc extended servicing at 18K miles which is way to long for a modern diesel engine.


Cheers

So i checked again today started the engine cold and i also took the cover off this time and it doesn't sound like the injectors on mine. It could be the hydraulic lifters or the turbo part rattling as the noise does seem to be from the front. Maybe when changing your oil get a flush done as well if some crud is partially blocking some oil pathway it may potentially solve the issue if its the hydraulic lifters.

Mine is a 2013 e220 cdi. Done around 68k miles and has full main dealer history except for the last service which was done by the dealer that sold me the car. Its my first diesel car and frankly I am already tempted to switch to a petrol/hybrid lexus. I have owned the car for 6 months now and in that time I have had to change a turbo boost pipe that cracked, i had the timing chain rattle which was caused by an additive i used, changing the oil fixed that. I did the engine mounts (they were more than half way worn at68k) and now this new noise on cold starts plus my drivers side door speakers intermittently cut out. For a 68k mile 9 year old luxury car i expected better. Also with ulez potentially expanding to outer London next year not sure if it makes sense pouring more money into a euro 5 diesel car.

 

[Tonygw]

Thats low milage for these kind of issues, Although age plays more of a factor in car deterioration these days, 9 years isnt that old. I have also replaced the turbo hose on mine, The oil in the hose degrades the rubber.

I am surprised the engine mounts needed doing also, they are known to fail but 68K and 9 years is a bit early, what made you get those changed?
I'm not sure if a Lexus would be any better these days but they do have an excellent reputation behind them. modern cars are far too complex, so issues seem to be inevitable.

But the expansion of Ulex is a worry, thankfully I don't live anywhere near London or any major cities so it's not an issue for me. (Yet!)

 

[Notamech]

Thats low milage for these kind of issues, Although age plays more of a factor in car deterioration these days, 9 years isnt that old. I have also replaced the turbo hose on mine, The oil in the hose degrades the rubber.

I am surprised the engine mounts needed doing also, they are known to fail but 68K and 9 years is a bit early, what made you get those changed?
I'm not sure if a Lexus would be any better these days but they do have an excellent reputation behind them. modern cars are far too complex, so issues seem to be inevitable.

But the expansion of Ulex is a worry, thankfully I don't live anywhere near London or any major cities so it's not an issue for me. (Yet!)

To be fair the mounts hadnt fully failed but you could tell they will need doing soon. For example starting and stopping the car would usually shudder. Also when warm and stopped at a red light there was noticeable vibration in the steering wheel, seat and centre console. Changing the mounts pretty much cured it. Also i had a look at the old mounts that were taken out and they were half collapsed i.e i could potentially continue using them with the above said issues if i could tolerate the issues, the old mounts didn't leak out or fail completely. I think age does tske its toll on rubber parts especially on a diesel engine as they run hot.

The turbo hose replacement cost me a whooping £250 to do at a mercedes specialist. Most of it was labour, diagnosis and vat the actual hose just cost around £54 or something.

I have a 2011 honda jazz as a small city runabout and have not spent a penny on it other then usual maintenance which motivates me to consider Japanese again. Ive always had these small niggles with all European cars ive owned be it vw, fiat or now this merc. Anyway im going to get some hydraulic valve lifter additive and see if that heps with this noise.

 

[Notamech]

@Tonygw was just wondering if you managed to sort out the issue. I have confirmed that there are 2 noises a lifter tick and the turbo wastegate rattle. The oil seems to drain down when sat overnight and on a cold start it takes time for the oil to pump the lifters up hence they tick before being pumped.

I tried the liqui moly hydraulic lifter additive, it made no difference but because it thickens the oil the engine is super smooth when warm feels like im driving a petrol car sometimes.

Anyway i plan to try a couple of things over the weekend if it doesn't rain. I'll be changing the castrol edge 5w30 and mann filter currently in my car to original mercedes oil and filter. I also bought an engine flush but not sure whether to use it or not as i plan to extract the oil with a pump rather than use the drain plug on the bottom. I can already see that the mercedes oil seems slightly thinner than the Castrol despite them both being 5w30 also the genuine merc filter looks a bit different with rubber/plastic coverings on the top abd bottom vs the current mann filter. i dont know whether these things will make a difference but lets see. Il do the oil change and report back.

I know you said you are due an oil change so just wanted to check if you got it done and if it made a difference? Also would be good to know what oil and filter is installed on your car currently.

 

[Tonygw]

Hi There
Sorry only just seen your reply. Yes my car went in for a B service, the changed the oil and filter. They only ever use PETRONA 5W30 MB sepc oil and genuine oil filter. THey are a Mercedes specialist and only work on MB cars, (MB automotive Loughborough)

I dont want to tempt fate but I haven't heard the noise since. I do get the rattle from the wastegate, had this for 3 years now. I dont think the MB recommended oil change intervals are good for the car, just to long between oil changes. To many particles build in the oil over time and wear critical components or block oil ways. (I had a new timing chain at 90K probably due to the car being serviced to the recommended intervals by the previous owner) I try to change the oil ever 6 months or 6K miles. Once myself using the suck it out method and once at MB automotive. May be overkill but I am ok with it.

I think an oil change may work for you, if you do use a flush it should be fine, although some recommmend doing two oil changes afertwards to get rid of any remaining flushing fluid.

Let me know how it goes as would be interested to know and hoping you sort it.

Thanks

 

[Gazwould]

With the pleasures of the egr and soot getting into the oil the oil does thicken as this builds up and held in suspension by the dispersants .

Just noticed the sound of a few hydraulic tappets slower priming on cold start myself and I'm due an oil change .

 

[Notamech]

Hi There
Sorry only just seen your reply. Yes my car went in for a B service, the changed the oil and filter. They only ever use PETRONA 5W30 MB sepc oil and genuine oil filter. THey are a Mercedes specialist and only work on MB cars, (MB automotive Loughborough)

I dont want to tempt fate but I haven't heard the noise since. I do get the rattle from the wastegate, had this for 3 years now. I dont think the MB recommended oil change intervals are good for the car, just to long between oil changes. To many particles build in the oil over time and wear critical components or block oil ways. (I had a new timing chain at 90K probably due to the car being serviced to the recommended intervals by the previous owner) I try to change the oil ever 6 months or 6K miles. Once myself using the suck it out method and once at MB automotive. May be overkill but I am ok with it.

I think an oil change may work for you, if you do use a flush it should be fine, although some recommmend doing two oil changes afertwards to get rid of any remaining flushing fluid.

Let me know how it goes as would be interested to know and hoping you sort it.

Thanks

Thats great to know. Yes I agree the recommend interval is fine if you only do motorway miles I guess. Most of my driving is city driving and im sure that means way more soot in the oil which needs changing earlier. Unfortunately this weekend had terrible weather so will do the oil change next weekend. Im still in two minds about the flush given that i will be sucking out the oil rather than draining it not sure the pump will get out all of the sludge etc that settles at the bottom. Will probably do a flush at the next oil change which will be at an MB specialist. I think the oil that MB sells as branded MB oil is infact Petronas so hopefully changing the oil solves my issue too.

 

[Tonygw]

Well unfortunately I can confirm the noise has returned. Its been about 4 weeks since the B service. I have heard it a couple of times now on cold start. I find I can only hear it with the bonnet up and it lasts for 2-4 seconds. A light tap/ticking, almost certain its a hydraulic lifter making the noise. A blip of the throttle and it goes away.

I'm reluctant to try a flush or lifter treatment for similar reasons to the ones you have mentioned. Plus the noise is only on cold start not all the time like a failed lifter would be.

I think for now I will just live with the noise. I've owned the car 31/2 years and its now on 117K miles. Not really high for these engines apparently.

If you do find a cure, let me know ..

 

[Notamech]

Well unfortunately I can confirm the noise has returned. Its been about 4 weeks since the B service. I have heard it a couple of times now on cold start. I find I can only hear it with the bonnet up and it lasts for 2-4 seconds. A light tap/ticking, almost certain its a hydraulic lifter making the noise. A blip of the throttle and it goes away.

I'm reluctant to try a flush or lifter treatment for similar reasons to the ones you have mentioned. Plus the noise is only on cold start not all the time like a failed lifter would be.

I think for now I will just live with the noise. I've owned the car 31/2 years and its now on 117K miles. Not really high for these engines apparently.

If you do find a cure, let me know ..

I did change the oil last Thursday and had some time to test. The noise did go away when i checked on the weekend. Could be down to higher temperatures over the weekend - was around 15 degrees here. Also the new oil is probably thinner. As it heats and collects soot it will thicken and flow less at startup. For me the thinner oil brought back a problem i thought i had fixed with the previous oil change... The dreaded chain noise. I think my tensioner is failing and it needs to be changed. Apparently they're a week point on these cars.

 

[Tonygw]

Yeah I do think temperature pays a big part. I didn't hear a thing this morning.

The timing chains can be a weak point on the OM651, I think the stop start system causes stress to the chain but the tensioners can also be an issue, mine got noisy at around 90K. I have no idea why Merc decided to run gears for most of the engine components but decided to use a bicycle chain to run the essential Cam shafts at the top of the engine.

Modern engines use chains but most manufacturers make the chains our of extra thin chocolate based steel. Its awful. I have some friends who work in the car trade and they complain about them a lot. I know Nissan and JLR (ingenium engine) have real trouble with timing chains. Maybe if they made them to be more robust it wouldnt be a problem.

Hopefully yours is just a tensioner, I know Merc did revise it, so if you change it get a genuine one and not aftermarket.