ML 270 W163 Squealing under accelration

[siblings2010]

So I have ML270 2001 pre face lift with 111k miles on the clock.

Lately it have been giving a annoying squealing noise under accelration. The noise is between 1600 RPM -2300RPM. This noise is not present when idle but is there when reved stationary.

I feels like the bearing of some sort but I cant diagnose which one. Has any one had the same issue.???

Please help before it gets worse... Any suggestions will be appreciated...

 

[c5jganno]

Sounds like a poly belt problem, does the noise come from under bonnet, maybe excessive play in water pump.
Gannons mercs and prestige in hertford

 

[siblings2010]

Sounds like a poly belt problem, does the noise come from under bonnet, maybe excessive play in water pump.
Gannons mercs and prestige in hertford

Thanks you for getting back so quick. Yes the noise defo comes from the under the Bonnet. Last owner had the water pump replaced about a year ago.

When you say Poly belt you mean the serpentine belt?? What is best way to check /sort this. I was thinking of taking the belt of and then checking every single poly but access is limited...

Any tricks of the tradde??

 

[BlackC55]

It could also be the alternator pulley. Use a long screwdriver against your ear to pin-point it.

 

[siblings2010]

It could also be the alternator pulley. Use a long screwdriver against your ear to pin-point it.

See I wouldn't know about the screwdriver bit... I will give it a go tomorrow - I am at work now ..

 

[siblings2010]

So I took the belt belt off and check all the belts the squealing still exists.

Decided to take it to Mercedes Specialist. He seems to think it could be the blocked Cat (Catalytic Converter) when the exhaust gases are trying to push through the blocked cat hence the Noise. He says that I could do away and remove the Cat which will get rid of the noise. Quote £150 Inc Vat

He also found the blown Injector No.5 which is making a hissing noise advise me to replace the injector seals extra for a£130.

I want to know if this can be done and removing the cat is not going to send the Emissions through the roof.

 

[Merc Owner 2B]

I'm sure that removing the CAT (where it is fitted as standard) is an MOT fail these days! I guess the point is "would the tester know it should be fitted to your car?"

One of our experts will advise though

 

[panason1c]

I'm sure that removing the CAT (where it is fitted as standard) is an MOT fail these days! I guess the point is "would the tester know it should be fitted to your car?"

One of our experts will advise though

I would expect the garage would 'Gut' the cat, removing the innards only. This would not affect the mot, due to it being a diesel.

Easy way to check for a blocked cat is to remove the clamp where the cat joins the manifold (under the air filter) and see if the noise is still present.