vibrating/rattling up front at idle.

Hey guys. when idiling, the car seems to have a big of a rattle/vibration coming from the front end somewhere, close to the firewall, right in the center it almost sounds like.. it kind of sounds like plastic. its not the valve cover. im sure its a pretty common rattle and it only happens at idle. if I give it 100 more RPM it goes away. anything I should check? sounds like it would be easy to fix, I just cant find where it could be coming from!!! any tips?

thanks.

Is your upper EGR cooler pipe secure? No missing bracket?

yup, that black bracket is there.

not positive if its actually "secure" though. but shes all bolted down. I havnt tried wiggling it TBH.

Sure it's not a bad alternator pulley?

Do the BEW car's have the same serpentine belt set-up as the ALH cars?

My serpentine belt tensioner was making quite a vibration/rattle at idle. If I put just a little bit of pressure on top of the tension cylinder with my thumb, the noise would instantly go away. Replaced tensioner and all was quiet again.

I've had a similar rattle. Check the bolts above your headlights. Mine were coming loose and rattling. Mine sounded like a loud rattle from the firewall at idle.


Mechanic's stethoscope is your friend.

Rembrant said:

Do the BEW car's have the same serpentine belt set-up as the ALH cars?

My serpentine belt tensioner was making quite a vibration/rattle at idle. If I put just a little bit of pressure on top of the tension cylinder with my thumb, the noise would instantly go away. Replaced tensioner and all was quiet again.

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Here are pictures of ALH and BEW serpentine belt diagrams. BEW belts are ribbed on both sides

The bottom pulley on the BEW is the power steering pump with the one above it being the AC compressor

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Any chance the radiator fans are running? Smaller fan on my wife's car was missing a section of its outer ring (between two adjacent blades) and the car would shake like crazy (and make noise) when the fans kicked on: I'd thought the thing was going to blow up, or perhaps the DMF was getting ready to lunch itself. Quite the relief to track it down to this.

Cambelt tensioner ?

Rembrant said:

Do the BEW car's have the same serpentine belt set-up as the ALH cars?

My serpentine belt tensioner was making quite a vibration/rattle at idle. If I put just a little bit of pressure on top of the tension cylinder with my thumb, the noise would instantly go away. Replaced tensioner and all was quiet again.

Click to expand...

You have a failed or failing alt pulley. Address that issue or the new tensioner will fail.

dervdave said:

Cambelt tensioner ?

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No. . .

jasonTDI said:

You have a failed or failing alt pulley. Address that issue or the new tensioner will fail.

Click to expand...

No no...I checked the Alt pulley at the time, and it was just fine...smooth, and operated as it was supposed to. That was 15,000 miles ago, and everything is still quiet and the serp belt runs nice and smooth.

I think the previous owner may have had an Alt pulley failure, and had it or the alternator replaced, and then left the sloppy tensioner installed for me to change later on.

Rem

ah. ok. You didn't mention that or the KM's on the car so it's usually the issue.

Do you have the factory plastic engine cover? I do and my rattle was from that. At an idle with it running, I pressed down on it and it went away temporarily. The rubber surround around the nut is worn. I like the look of the cover, so I'm keeping it. Just have to figure out how to fix it because they don't sell the grommet I have found. The small pop on ones, yes, but not the big one.