kpp

Hello,

I have just found that my new A250 W177 emits ugly noise when the engine is cold. It takes about 2-3 minutes and after that time the engine starts to work fine, it is quiet. What is really interesting here, my car has only about 600 km of mileage now.

Here is a video from YT that presents the problem (please note the video is not mine, but the noise is exactly the same):

Does anyone have any idea what may cause that noise? According to me, it is not normal and I am afraid it may cause serious engine malfunction in future. I had similar noise in my old VW car, I ignored it and after some time I had to replace its engine as it fell apart.

I found in the Internet that more people have similar problem. They have reported it to dealer/service, but they have always got the same answer: "It is ok, the engine works fine". So, as you can see dealers ignore the issue. What should I do? I do really like to sort the problem out, I am really afraid that it is something serious.

Thanks in advance.

Regards,
KPP

LILBENZ230

I suspected before the video that this was perhaps secondary air injection, but that sounds almost like a belt chirp?

nairpic20

Mine makes the same noise, 33k km. Did you manage to find out the reason?

kpp

I have not found it so far.

This clicking noise is driving me crazy. It is present only when the engine is cold.

I am starting to believe it is caused by a PCV valve, I found some info on US forums that they might be a bit noisy when the engine is cold...

190Efan

As long as it continues to go away after a couple of minutes as it might be part of the start up procedures with all of the computers, I don't think I'd worry about it at this point. If it starts to happen more consistently and continues to happen after the first couple of minutes then I would say that there's an issue. At this point, I would make sure it's been documented with the dealer for possible future warranty purposes and then monitor it to see if it's getting any worse. Just my 2 cents.

LILBENZ230

Mercedes tend to be very industrial sounding anyway, but I am not sure this is normal.

kpp

In my opinion, it is either a PCV valve or a high pressure fuel pump. I have a way to verify it potentially, but I do not want to loose a warranty.

According to me, it is not normal. First of all, the noise is annoying. Secondly, I am afraid I may expect expensive repairs in the future. It is strange that the new car sounds like this. You can check many non-premium cars and I bet it will be difficult to find a similar case.

EDIT:
If it was normal, all a250s (and other models with the same engine) would sound the same. I found info on one forum that someone compared cold start of two similar A250s and one of them was nice and quiet and the second one was noisy as hell. So, it is not a 'feature'.

Vampire1984PL

I belive it could be as weak quality control on each engine parts inside or engine equipement. I belive its all ok but as MB quality is going down it could be like, some other A Class do not rattle generate resonating sounds, some not

190Efan

I listened to the audio again and what you're hearing is the valves tapping. The valves on my 1991 190E do the same tapping but not quite as loudly. That's a pretty vintage MB engine sound. I've owned my car for almost 30 years and never had a problem.

kpp

@Vampire1984PL , it is so called mass production.

@190Efan , I am not sure if it is a sound of ticking valves. Shouldn't it go away after a few seconds when the oil hits upper parts of the engine? I had a metal ticking noise in my old car and it always lasted up to 10 seconds. Also, the sound in the recording is more 'plastic' in my opinion. In my car, it goes after few minutes, when the engine gets hot.

190Efan

Hi kpp, it sounds to me like it is the valves tapping. I can here my valves lightly tapping well after I've started my engine. That's a vintage MB engine sound. So long as it's not a really loud banging noise. I don't think you have an issue at this point. You've got it documented at the dealer so I would just drive it and see what happens. If it gets louder and starts really banging then I would take it in to the MB dealer to have it checked.

RALEIGH BIBIANO

Hello everyone! I hope that this msg finds you well and healthly.
I've noticed the same abnormal noise coming from engine while it's cold (current mileage: 8000 km). Additionally, after own initial diagnosis, I believe that it's may have been caused due to rocker arm pushrod hidraulic camshaft lifter oil low pressure.
Anyway, I'll share it with MB dealership...
Does somebody ever officialize it with local dealers in your province?
If somebody has any kind of news about that, please, let us know.
Regards!

Vampire1984PL

After night

https://drive.google.com/file/d/1Ze6...ew?usp=sharing

https://drive.google.com/file/d/1shH...ew?usp=sharing

190Efan

It's pretty common to hear the valves tapping on an MB engine as I've noted previously. Only if it sounds like a sledgehammer would I be concerned.

kpp

@Vampire1984PL your car is quiet, I would not be very afraid of that, compare it to the recording from the first post of this thread.

Btw, I found something strange today. I entered engine info menu in MBUX (central panel, section with four charts). It shows 0 kPa pressure in my car. Isn't that strange?

kpp

EDIT: Actually, the pressure chart works fine I guess, it is non-zero when driving.

Vampire1984PL

Yes, its turbo pressure and starts after some rpm

sosy2k1

Hi mate, my A250 had noise same like yours, do you fixed? Thank you so much

lululu

DID YOU GET IT FIXED?

lululu

what fixed it?

Patrickb

Hi , I own a W177 A220 with the same engine as the A250 with13000km on the clock and has the same sound when cold and disappears after 5 minutes driving, I’ve taken the car to the Dealership and they made made a visual check but nothing was found ,
they contacted Mercedes Germany and said that the engine had to be removed for inspection and be run off the car to find the solution.
they also said probably a new engine will be fitted .
the good thing is that my cars warranty expires in two days time and I just got it on time , I am waiting for results from the dealership as I handed the car yesterday
I will post a video with that same noise

190Efan

Every case is certainly different but I'm glad MB is taking care of your car.

lululu

Its the timing chain tensioner

Patrickb

[QUOTE=lululu;8341540]Its the timing chain tensioner[/.
Ive heard that from a mechanic but I’m still waiting A reply from MB Germany as they told me that there would be a recall on all W177 A220 / 250 as the have the same engine.

kpp

Hey Patrickb,

Thanks a lot for sharing that info. Can you please keep us informed about your case? Did they reply to you? What does cause this issue? Do you know when we can expect a recall action and what is the scope of it?

I do not hear any noise when there is cold outside. But, when there is about 15-25 degrees, my cold engine is loud and I am afraid it is getting louder and louder. I have visited a few dealers in Poland and every single one either did not hear anything or told me it is 'normal' and I should not worry about that. It is of course bullsh*t, they just do not want to do anything with my car... And in a few months I will be out of warranty, so I need to get it sorted out (or at least diagnosed) as soon as possible. And dealers refuse to cooperate... Welcome to Poland...

Also, I found some info on the external forum (I know it is not this forum, but let me share the link, it may be helpful for people with the same problem):
About A250 problem on some external forum
I really recommend you to read that post, one user got info that "...the chain in the engine being slightly too big...". Nice quality and testing on users...