E320 CDI avantgarde 52 rattling noise

[astorz]

I really would appreciate any suggestions as to what this could be...I have a rattling noise when I put my foot down on the accelerator especially when the car goes over 30mph, when it is travelling without throttle there is no noise, it has been into Mercedes twice now - the first time they replaced the catalyst, the next time the exhaust - fortunately all under warranty - any suggestions what it could be - it is going back next week....it almost sounds as though something is rubbing/catching against the wheel at times - but can't be as I said only happens when my foot is on the acelarator

 

[astorz]

I really would appreciate any suggestions as to what this could be...I have a rattling noise when I put my foot down on the accelerator especially when the car goes over 30mph, when it is travelling without throttle there is no noise, it has been into Mercedes twice now - the first time they replaced the catalyst, the next time the exhaust - fortunately all under warranty - any suggestions what it could be - it is going back next week....it almost sounds as though something is rubbing/catching against the wheel at times - but can't be as I said only happens when my foot is on the acelarator

 

[brandwooddixon]

A common problem is exhaust heat shields working loose. They are aluminium and the steel mounting bolts corrode through so that the become loose. Larger washers and instant gasket easiest fix.

Other than that I suppose the noise could be engine related, but the question is does it only occur when the car is moving? If you place the engine under load when stationary does it still do this? (Stick it in drive, foot firmly on brake and press the accelerator to bring the revs up).

Have someone listen for the noise whilst doing this just DONT let them stand in front of the car!

If there is no rattle then that most likely rules out anything engine and exhaust related, leaving you with transmission, suspension and brakiing components.

 

[astorz]

thankyou for your comments - visiting mercedes monday morning - the noise only happens when car is in motion - tried it when car is standing still when in neutral and applying foot to acelarator.

 

[hawk20]

I really would appreciate any suggestions as to what this could be...I have a rattling noise when I put my foot down on the accelerator especially when the car goes over 30mph, when it is travelling without throttle there is no noise, it has been into Mercedes twice now - the first time they replaced the catalyst, the next time the exhaust - fortunately all under warranty - any suggestions what it could be - it is going back next week....it almost sounds as though something is rubbing/catching against the wheel at times - but can't be as I said only happens when my foot is on the acelarator

Fuel pump makes a noise sometimes. You don't show your location but if you are near enough to Southampton they have a fabulous MB diagnostic guy I could put you in touch with. He also covers Winchester, Chichester and Portsmouth.

 

[brandwooddixon]

Have you tried it with the car in drive, foot hard on the brake and foot on the accelerator?

 

[The Rock]

I'd go along with brandwooddixon's first suggestion. My heat shield has corroded around the fixing bolt too and rattles like crazy.

Rock

 

[astorz]

I am in London

 

[astorz]

I will try that.....typical - was due to go to Merc this morning...could I hear the rattling noise...NO....so cancelled it.
Will try that anyway.
Really want to try and get to the bottom of this whilst my car is under the used car merc warranty which expires in December....but thanks once again for your suggestion

 

[astorz]

sounds the most feasible of suggestion...though when they changed the exhuast and catylist you would of thought they wuld have checked everything......luckily this is not costing me a penny as I am still under the merc used car warranty until dec....