shotgun_banjo

Okay this is starting to irritate me now as after 3 replacement of the exact same parts the engine squeaks like a 1980 truck that had never been taken care off. This happen approx. 4-6 months apart after replacement. I was told that this was a known issue on the old engine but there should be a fix after x amount of years.

Are there any MB mechanics on the forum that know the cause of this loud squeak? The car is only 2.5 years old and only has 20k kilometers on the motor and still smells like new. So just imagine when the wife is driving it and you get a call screaming "people are looking at me like I drive a broken Mercedes and seems like to them I don't care about it...did the dealership fix this last time!?" you barely have any explanation to her until I drove it this morning and I got the same eye stare from fellow motorist and most of them shacking their heads in disbelief I felt what my wife felt a few days ago.

The mechanic told me the noise doesn't affect any performance but the humiliation of having the noise is the most damaging aspect of it. Apparently the head office at Germany insist of just replacing the parts but since they did already 3X I doubt it is those parts that are causing the problem and something else.

Here is how it sounds right now....

https://www.dropbox.com/s/yegxpgovsi...2019.04.16.mp4

bop11

This is caused by an alignment problem between components. Something is not square or not at the proper front to back location. .The power steering, alternator harmonic damper etc. Very hard to fid. Could be a mount that is drilled incorrectly so that the pulley runs at an angle or could be the pulley itself. Running at an angle to the belt center-line puts a torsion in the belt. The idler pulley is the weak link but probably not the cause as most MB don't have this problem and it is unlikely that you would get 3 bad units. It shows up at the idler because the other components have strong enough bearing systems to resist this twist ( multiple berings space at front and backwith long shaft in between) but the idler does not. The twist is all taken on the bearing race which first destroys the bearing seal and then the ***** and race gall and make noise. Determining which component is out of line is a painstaking operation where either components are replaced and wait or the belt is removed and the pulley on each component is rotated to check for wobble, or out of alignment with the perpendicularity of the other components, or location too far forward or too far back. By now some indication of scuffing might show up on the culprits pulley and those that are between the culprit and the idler in the direction of rotation.

shotgun_banjo

Okay you got me on the misalignment and lost me on the rest. We will see what the master tech will do as he said he will do a modification on the parts. Hopefully that will fix the problem and if this thing pops up again for the fifth time I'll go crazy to MB Canada.

chinoloco

I have the same problem. The dealer replaced the belt and bunch of other stuffs three times in 2 years under warranty. The high pitch chirping noise still came out once in a while. Two weeks ago l asked my brother in law to put in an aftermarket belt to see if that helps.

My 2011 GLK has only 31,000 miles.

If the noise comes out again, l am going to trade it in for a Lexus.