5 Series 1989 –
1995 (E34)
Radiators
The radiators are prone to develop cracks in the plastic end
caps, requiring replacement.
Front
Control Arm Bushings
The rubber bushings, which isolate unwanted
vibration during braking, age much like the rear shock mounts. They start to develop small
tears and cracks, then progress to completely broken out of their
mounting. The normal
symptom is vibration in the steering wheel under light
breaking. Ignoring this
will result in uneven tire wear. Larger than stock tires /
wheels amplify the symptoms.
V8 Power
Steering Hoses
The power steering hoses on the V8s will
leak. The low pressure
hose can be repaired, carefully cutting the crimped on clamps and
replacing the flexible hose section. The high pressure hose
requires replacement and is a fairly expensive part which is in very
tight quarters.
V8 Valve
Cover Oil Leaks
The V8 valve covers leak around the inner
and outer gaskets. The outer gasket leak leaves a visible on trail
of oil on the head. An
inner gasket leak isn’t visible until the covers are removed from
the engine, exposing a lake of oil in one or more spark plug
holes.
V8 Vacuum
Plate
There is a plate on the rear of the intake
manifold that provides crankcase ventilation. The internal diaphragm
fails, requiring replacement.
This involves removal of the intake manifold. The symptoms are rough idle,
a whistling noise, and a “Check Engine” light.
V8 Thermostat
Covers
The early V8 came with a plastic thermostat
cover that had a high failure rate. Most of these have been
replaced with an aluminum unit by
now.
Electric Seat
Drive
The seats have several drive mechanisms in
each, which include drive cables. The cable housings are
slightly too long, and over time, the cable backs out of the driven
mechanism, resulting in no movement of that part of the seat. The
repair involves opening the seat, removal of the cable housing,
cutting a section out of it and putting it back together with a
splice of rubber hose and hose
clamps.
Microfilter
This isn’t a problem area, but something to
be aware of. Beginning
6/90, a microfilter was added to filter contaminants out of the
cabin air. The only
questionable part of this decision was its placement. Buried in the dashboard /
console, replacing it requires removal of the glovebox, part of the
air ducting and some electronics. The difficulty of
replacement results in it sometimes being ignored, resulting in
inadequate airflow through the system. Sometimes you may believe
the A/C is failing when it just needs a new filter
Brake Light
Switch
The brake light switch will begin to cause a
“Brake Light Circuit” warning intermittently. This will continue until the
switch is replaced and it is good to replace all 3 bulbs at this
time.
| 
