Hunting down the rattle.

M

Matty_Z4

Member
Some of you may have seen in my intro post a couple of months back I had a nasty rattle from the front of the car when pulling away/driving at low load low RPM 1900 - 3000.

I can only really describe it as a metallic tinkling noise that is driving me crazy.

From the video posted in my original post a couple of you mentioned to get it looked at as it sounds quite bad. Its improved much since the video was taken but its still there and i really want to get to the bottom of it. So here is the story so far.

Went to a "Backstreet" garage who rebuilt the DISA at my request while they were doing the tracking rods and wishbone bushes. No improvement (well the handling better but thats nothing to do with the rattle)

Then it had its service/MOT at a specialist who gave the car a once over, replaced a sticking brake calliper (again nothing to do with the rattle) and told me it sounds like the Flex plate or a baffle is loose in the exhaust. Gave me the number for his exhaust guy who had the car for a day and messed around with some heat shields and rusty bolts then charged me for the privilege. (no difference)

I have now taken it to a different specialist who had the car for a 2 day diagnostic, and spent most of the time chasing a noise that I had never heard the car make and can't make it do it myself so I'm not worried about it. But did come back with a list of advisories to keep an eye on and get done in due course.

  • Collapsed Vacuum line on the brake booster - Not fully collapsed but looks squashed.
  • Collapsed breather line from the Cyclone valve down to the oil pan
  • Leaky oil filter housing gasket.
  • Weeping shock (MOT advisory so knew about it)
  • Bowed radiator bottom.
  • Someone has been in the "bell housing" (is that still what its called on an auto) as the inspection cover is missing that lets you look at the flex plate/torque converter.
He wants to replace the collapsed hoses around the cyclone valve (PCV) as he has mentioned in his experience collapsed hoses here can make the top end rattle and sound like its going to explode so the collapsed hose could very well be the source of my noise.

The other noise that he found he is not sure on but could very well be flex plate related, the sound is hard to describe its between a twanging spring and a sneeze like you get from those silly ricer cars with the dump valve/screamer pipe (no i don't have a turbo or any odd electronic gizmos)

Im slightly confused at how a collapsed breather could make this rattle or what is actually rattling so am hoping some forum wisdom can enlighten me and if the breather doesn't fix the problem where to start looking next.

Ive convinced myself its VANOS/timing chain related but the specialist doesn't think it is just yet.
 
Link to original post would be helpful. I can't see how the PCV hose would be related to the rattle either but it is a very common fault that is worth getting rectified for sure.
 
ph001 said:
Link to original post would be helpful. I can't see how the PCV hose would be related to the rattle either but it is a very common fault that is worth getting rectified for sure.
Click to expand...

Would help wouldn't it, link to the old post. https://z4-forum.com/forum/viewtopic.php?f=11&t=111459&p=1609280#p1609280

Ive taken a new video today, just trying to get it onto youtube and will link it later if the microphone has picked up the rattle, as its much quieter than the one in the original video but its still there.

EDIT: There is too much noise in the video I took today will have to try another one with a calibrated microphone.
 
I think the first thing to nail down is if it is drive train related or engine related. First question: Can you hear anything at all when revving in neutral?

EDIT: Ah, I see you mentioned at the end of last thread that the car still did it in Park. If that's still the case then you need to take the tension off the serp belt so it doesn't spin all the ancilliaries such as aircon, alternator, water pump, idler rollers.
 
ph001 said:
I think the first thing to nail down is if it is drive train related or engine related. First question: Can you hear anything at all when revving in neutral?
Click to expand...

It only does this when im driving and not at a standstill but when I was at the specialist last week he was revving it when in park and you could hear the noise from outside the car but I cant make it do it.

So I guess that is a yes.

EDIT: Heres the link to the video I took today, warning there may be some bad language at the start of the video. The rattle can be heard almost from the initial left turn up to the first right turn on the video. (super feint need a good pair of headphones to hear it.)

[youtube]47ON6Ah9M20[/youtube]
 
Video unavailable - make sure it's set to public in Youtube. So are you saying it makes the noise both when revving in neutral and when driving but it's much more pronounced when on the move?
 
As a small aside, can I suggest that next time, you update your original thread rather than starting a new thread about an existing problem? That way, everyone will be able to read what you've reported/tried to date.
 
ph001 said:
Video unavailable - make sure it's set to public in Youtube. So are you saying it makes the noise both when revving in neutral and when driving but it's much more pronounced when on the move?
Click to expand...

yes that pretty much sums it up, the rattle is much louder when on the move (Still really feint on the video much louder in person)

So its been in today and has had the Collapsed hoses, Oil filter gasket and Aux belts replaced, no change to the noise. Going to bring it back in about a couple of 3 weeks for him to have another look.

I took another couple of videos on the way back from the garage, links below. Hopefully I got the privacy settings right this time.

[youtube]RI-kRWg3l8k[/youtube]

[youtube]BSh3aYEMbwk[/youtube]

[youtube]RqublVAvjO8[/youtube]

[youtube]8YGF0WtVL8w[/youtube]
 
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