3 Series E46 316i (M43TU) SAL
MK-23/Hack
Baugruppe/Group: 33
33 01 99 (403)
weltweit
all countries
02/1999
Snapping, knocking and smacking noises from the rear of the vehicle (rear axle/fuel
tank)
E46 saloon
Complaint:
Snapping, knocking and smacking noises from the rear of the vehicle when pulling away,
cornering or driving over an uneven surface.
Cause:
When driving over uneven surfaces or when cornering, the rear axle springs compress and
the uppermost coil of the barrel spring stick to the spring mounts.
When the spring then extends again, the coil is torn away from the spring mount causing
the noise described above.
These noises are transferred through the upper spring mount to the body and amplified.
Important!
These noises are frequently misdiagnosed as coming from the fuel tank.
This assumption is reinforced by the fact that the noises (temporarily) disappear
when the fuel tank is given additional support with tensioning straps.
This is a result of the vehicle being raised with a hoist. The relief of all load on the
(rear) wheels causes the position of the barrel springs relative to the spring mount
to change, in turn causing the noises to (temporarily) disappear.
On new vehicles, the fuel tank should in any case be completely filled to allow the
tank to settle properly due to the weight of the fuel.
The plastic fuel tank on the E46 is (as on the E39) elastically mounted by rubber-
bonded tensioning straps with a foam cushion between the tank and the body.
This mounting always allows the fuel tank a vertical movement of about
5-7 mm. Vertical forces (e.g. when a mechanic is checking the vehicle) then cause
greater travel.
This play is required for the swelling of the fuel tank under the weight of the fuel
(the swelling of the fuel tank under the weight of fuel is completed after about 6-12
weeks under fuel) and when the system is heated up (e.g. at high ambient
temperatures).
It is thus not permissible to provide additional support for the fuel tank with
tensioning straps.
This design can give the impression of the fuel tank being loose.
Affected
vehicles:
E46/4
start of series production until July 1998
Remedy:
Coat the upper mounts of the rear axle barrel springs with talc.
Important!
Do not carry out any measures on the fuel tank !
Procedure:
1.
In case of complaint, raise the vehicle with a hoist and remove the rear wheels.
2.
If the spring mounts and barrel springs are very dirty, wipe them clean with a dry cloth
(do not remove barrel springs !)
Note:
SI Snapping, knocking and smacking noises from the rear of the vehicle (rear axle/f
BMW AG - TIS
19.01.2013 09:28
Issue status (12/2007) Valid only until next DVD is issued
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