M156 enquiries
Thank you. Merely amusing myself with fear, then 
I believed I heard a rattling noise.
I have evidently seen an excessive number of YouTube videos that seem to explain this little noise at the first start-up as a problem with the cam adjustment.
I believed I heard a rattling noise.
I have evidently seen an excessive number of YouTube videos that seem to explain this little noise at the first start-up as a problem with the cam adjustment.
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Hannah_Baker2000
- Senior
- Posts: 84
- Joined: Thu Mar 03, 2022 7:50 pm
The M156 engine is characterised by its high level of noise, which is a common trait among all AMG engines. However, this noise does not indicate any significant problems with the engine. However, I must offer a disclaimer that it is very difficult to perceive auditory information in a video.
I have personally seen an M156 engine in person that exhibited a single lifter bucket and cam lobe wear. The resulting ticking noise was characterised by a lower pitch, slightly increased volume, and less frequent occurrence compared to the typical ticking sound.
The reason for this is likely due to the initial wear only impacting one or a few specific buckets/lobes. As a result, the other 15 buckets/lobes remain unaffected and produce regular sounds. Consequently, you can only hear the abnormal sound in one out of every sixteen buckets/lobes.
An authority will verify my statement, but I think that even in the case of healthy buckets, there is an initial increase in noise due to the hydraulic pressure taking some time to build up and the oil to circulate.
When a bucket gets stuck, it takes a longer time for pressure to build up, resulting in a prolonged ticking sound. Once the bucket fails, it becomes physically damaged, causing the noise to become more noticeable.
If I am mistaken, an authority will surely rectify my error.
Revised to include: A commonly accepted guideline:
If the ticking is consistent and normally decreases in loudness after one or two seconds, then it is likely acceptable at present.
If there is a tick that is characterised by a lower pitch, less frequency, and longer duration, it is likely indicative of a problem.
I have personally seen an M156 engine in person that exhibited a single lifter bucket and cam lobe wear. The resulting ticking noise was characterised by a lower pitch, slightly increased volume, and less frequent occurrence compared to the typical ticking sound.
The reason for this is likely due to the initial wear only impacting one or a few specific buckets/lobes. As a result, the other 15 buckets/lobes remain unaffected and produce regular sounds. Consequently, you can only hear the abnormal sound in one out of every sixteen buckets/lobes.
An authority will verify my statement, but I think that even in the case of healthy buckets, there is an initial increase in noise due to the hydraulic pressure taking some time to build up and the oil to circulate.
When a bucket gets stuck, it takes a longer time for pressure to build up, resulting in a prolonged ticking sound. Once the bucket fails, it becomes physically damaged, causing the noise to become more noticeable.
If I am mistaken, an authority will surely rectify my error.
Revised to include: A commonly accepted guideline:
If the ticking is consistent and normally decreases in loudness after one or two seconds, then it is likely acceptable at present.
If there is a tick that is characterised by a lower pitch, less frequency, and longer duration, it is likely indicative of a problem.
Thank you, this information was quite useful!
Indeed, I am aware that video diagnosis is challenging, which is why I am likely to arrive to the same conclusion myself! Additionally, it should be noted that AMG engines include a considerable level of noise, which may provide challenges for those who lack expertise in this area, especially if they are not well-acquainted with the particular engine in question.
Thank you once again for the valuable guidance and information; I want to revisit and examine it further.
Indeed, I am aware that video diagnosis is challenging, which is why I am likely to arrive to the same conclusion myself! Additionally, it should be noted that AMG engines include a considerable level of noise, which may provide challenges for those who lack expertise in this area, especially if they are not well-acquainted with the particular engine in question.
Thank you once again for the valuable guidance and information; I want to revisit and examine it further.