B6 A4 BEX 1.8T Metallic Rattle

[Neuk]

Hi all

I have searched for and read various topics relating to my issue but would also like the input of others, regarding a metallic rattle like sound I have in my B6 A4 BEX 1.8T engined Avant...

When she is up to full operating temperature, not just water temperature at 90 Deg C, there is a metallic sounding rattle that can be heard between around 1500 and 2000 rpm. It can be heard when going up or down the rpm range, when on or off throttle, in gear,, out of gear, clutch engaged or disengaged, stationary or moving. Initial research pointed to the fan/accessory/serpentine belt tensioner so I replaced it along with the belt as it is a relatively easy and quick job but that didn't solve the problem. I have a list of possible causes but it sounds like it is coming from the head and although I haven't pinpointed the exact location, I do have an idea of what it could be...

Any thoughts or input would be greatly appreciated...

Cheers
Nic

 

[rickc]

Hi Nic,

Does it still do it when the aircon is switched off (i.e. in Econ mode)?

I have a 2011 VW Polo that makes a similar noise when the aircon is on but is quiet when it's off. I haven't done anything about it yet so don't know if it's actually a fault.

Just thought it may give you something else to investigate.

Rick.

 

[Neuk]

Hi Nic,

Does it still do it when the aircon is switched off (i.e. in Econ mode)?

I have a 2011 VW Polo that makes a similar noise when the aircon is on but is quiet when it's off. I haven't done anything about it yet so don't know if it's actually a fault.

Just thought it may give you something else to investigate.

Rick.

Rick

Thanks, the aircon is one of the possible causes, I used it a lot while on holiday this last season but haven't used it much since getting back home. The noise is there with the aircon on or off, hence me believing it is not the issue...

Cheers
Nic

 

[Neuk]

I took a short video of the sound from inside the car this morning...

Audi Metallic Rattle - YouTube

It is tough to get it from the engine bay when I am alone as it doesn't make this noise at idle, as you can see in the video. Any thoughts?

 

[Neuk]

So, it looks like the metallic rattle is being caused by the cam belt damper, which is a relief except I am struggling to find any locally. I am waiting for a quote from a local Audi dealership but notice that there is merely a letter difference between the VW and Audi part numbers...

VW:

http://www.ecstuning.com/Volkswagen-...ming/ES260966/

Audi:

http://www.ecstuning.com/Audi-B6_A4-...ming/ES279999/

Are these two parts interchangeable at all?

 

[Neuk]

I found out that there is a difference between the cam belt damper for transverse and longitudinal mounted 1.8T's so they are not interchangeable...

 

[GeoffDunk]

I had a very similar problem with both an old Golf GTI 16V (MK3) and my last Passat, both where caused by the Cat heatshield coming loose. They are held to the CAT's with captive nuts and the nuts are pressed in and come detached over time. No hole in the exhausts though.

Just a thought.

 

[Neuk]

I had a very similar problem with both an old Golf GTI 16V (MK3) and my last Passat, both where caused by the Cat heatshield coming loose. They are held to the CAT's with captive nuts and the nuts are pressed in and come detached over time. No hole in the exhausts though.

Just a thought.

Geoff

Thanks for the input, someone did mention this and I had a poke around but couldn't see or feel anything, I'll give it another try this weekend when I get a bit of time. I took the car to a friend of mine, who although he works at a local VW dealership is a genius with VW and Audi vehicles, he thought the sound was coming from the cam belt area. When he pulled the cam belt cover away he noticed the damper moving excessively and that there was some slack in the belt…

Cheers
Nic

 

[AlexGSi2000]

I had a similar issue, thought my engine was toast - turned out to be an exhaust clamp that had become loose and resonated at a certain rpm.

 

[Neuk]

I had a similar issue, thought my engine was toast - turned out to be an exhaust clamp that had become loose and resonated at a certain rpm.

Alex

Thanks, Geoff mentioned the same issue, do you have any pictures of which clamp exactly? It would really help...

Cheers
Nic

 

[AlexGSi2000]

Alex

Thanks, Geoff mentioned the same issue, do you have any pictures of which clamp exactly? It would really help...

Cheers
Nic

Don't have any pictures, but it was obvious when the car was lifted on ramps.

 

[Neuk]

Don't have any pictures, but it was obvious when the car was lifted on ramps.

Thanks Alex, I'll jack the car up this weekend and do some poking and prodding, would be great if it was something like that although the cam belt damper didn't look too great...

 

[Neuk]

And the metallic rattle is gone, cam belt damper and cam belt replaced sorted the issue out. I also had the 150k km service done including a gearbox oil change...