All comments and suggestions welcomed!!

UK forum for general and technical discussion about the Z3 roadster

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

All comments and suggestions welcomed!!

Post by Southernboy » Thu 20 Sep, 2018 13:32

After my earlier post on the fuel gauge issue, I am now looking for the "rattle in the back"...
I have checked all the obvious items like shocks, exhaust, tank strap rubber cushions and bumper weights and all to no avail.
So... anyone who has come across more unusual causes, please pass on the info so I can check those too.
The rattle is only audible when the speed is low and the car isn't revving to loudly. It is apparent when driving over small frequent bumps - something like one would feel driving on cobble paving perhaps.
Once the speed is up around 30 - 40mph, I can't hear a thing.
I hope someone will have discovered the source and will share their knowledge.
"Normal is overrated"
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PaulI
Joined: Sun 28 Dec, 2003 19:37
Posts: 23

  Z3 roadster 2.8
Location: Weybridge, Surrey

Re: All comments and suggestions welcomed!!

Post by PaulI » Thu 20 Sep, 2018 15:08

Check the spare wheel, the cradle and all the parts, and that's its all installed nice and firm!

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

Re: All comments and suggestions welcomed!!

Post by Southernboy » Thu 20 Sep, 2018 15:52

Cheers Paul...did that - spare wheel isn't fitted at the moment and everything associated is really secured well.
Somewhere I read that there is a "ball valve" fitted on the top side of the tank... Same system as a toilet ball valve. Apparently it's there to prevent fuel spillage in the event you roll the car.. Can't see the sense though... why have a valve at all ?? there are other vents for the tank already. I just thought that if that was true, maybe my ball is rattling in the valve.. :lol:
"Normal is overrated"
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NZ00Z3
Joined: Thu 23 Jun, 2016 02:26
Posts: 68

  Z3 roadster 3.0i

Re: All comments and suggestions welcomed!!

Post by NZ00Z3 » Thu 20 Sep, 2018 22:39

I have a similar rattle that has been put down to worn CV's on the half shafts. The half shafts have about 10 mm longitudinal movement when you reach under the car and slide them to and back. If I set the shaft to the diff end, the rattle goes away until it works its way back. The outer CV has the slip joint and the inner CV should be tight but wear of the CV (110,000 miles) gives it some travel. Have checked it against a couple of other Z3's which don't have any shaft movement or the rattle.

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

Re: All comments and suggestions welcomed!!

Post by Southernboy » Fri 21 Sep, 2018 06:25

Thanks buddy - I'll check those CV joints - could be the culprits.. :cheers
"Normal is overrated"
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Z3 Upgrades and Additions

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

Re: All comments and suggestions welcomed!!

Post by Southernboy » Sun 23 Sep, 2018 07:32

To close this thread - I found the rattle !!!
On friday I stripped off the old roof and yesterday I fitted a new one. In the process of stripping, I was quite surprised to find the 19 large self tapping bolts at the back window area which hold the sealing and tack strips were quite loose. Anyhow, after installing the new roof, which requires adding strips of butyl for sealing, I parked the car in the sun so the butyl would soften before I did the final torque on those screws - I want to get max compression of the butyl for the best possible seal. Well the upshot of it all is that the rattle has gone. So I assume it was the plastic sealing strip or the tack strip which was the culprit due to the somewhat loose screws...
Thanks for the replies guys.
"Normal is overrated"
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rambo
Sponsor 2018
Joined: Tue 16 Aug, 2011 18:17
Posts: 83

  Z3 roadster 2.0
Location: Grimsby

Re: All comments and suggestions welcomed!!

Post by rambo » Wed 03 Oct, 2018 11:09

Always look for loose batteries rolling around
I did that in 1966 with my MGB and the culprit was a LR14 1.5 volt battery!!
Glad you sorted the problem

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Gazza
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Joined: Tue 04 Oct, 2005 21:58
Posts: 9348

  M roadster S54
Location: Romford Essex

Re: All comments and suggestions welcomed!!

Post by Gazza » Fri 05 Oct, 2018 20:34

A friend of mine had a strange bump noise when accelerating and also under braking.

On further investigation it was a water bottle under the passenger seat :lol:
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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