This article is from the Watercooled VWs General FAQ, by Jan Vandenbrande with numerous contributions by others.
A: VW makes cars, which is an assembly of components, but not all components
are made by VW. In fact, VW makes mainly the body and the power train, the
rest they buy from elsewhere.
The OEM parts can often be had for less than buying the same VW part.
Most of the ones listed below will have a VW part number, but are also to
be had directly from the OEM w/o the VW part number.
For example MANN makes VW filters with the VW label, but the same filter
also exists with the MANN label.
In other cases, VW uses parts w/o restamping or hiding the OEM name for
marketing reasons, e.g., Recaro seats, BBS rims.
The OEM suppliers are (not exhaustive, changes frequently):
ATE Brake components (master cylinder)
BBS Rims, some cars, not restamped
Beru Electrical components (rotor, cap)
Boge Shocks & components
Boka Waterpump, Mexican made VWs
Bosch Many of the electronic components (e.g. Alternator)
Fuel, other filters, FI, antenna
Continental Drive Belts, Tires (note, they also make Uniroyal
Semperit, Gislaved and General Tires)
FAG Brake components, master cylinders, wheel bearings
Fichtel & Sachs Clutches, shocks on some cars
Fuba Roof mounted antenna (flexible one)
Gillet Exhaust (at least at some point)
Girling Front disc brakes < 81, F&R on Passat >8?,
Rear 16V GTIs
Glazurit/Hoechst/BASF Brand of paint used.
Unclear who produces water based paints in newer VWs
Golde Sunroof Maker
Hella Lights, markers, bulbs
Hengst Oil filters VR6
Hirschmann Antennas, some VWs
Keiper/Recaro Makers of VW Seats (not *real* Recaros)
Kesley-Hayes Front Brake calipers most > 81 cars
Leistritz Exhaust (for some--usually VR6 cars)
Loebro CV Joints
M.A.N.N. Oil & Air Filters
Matsushita Heidelberg (VI & others) radios.
Motorola Alternator in some US made cars
Recaro Seats, some cars, not restamped
Ronal Alloy rims some Audis/VWs
Sekurit Windshield, windows
Sofica Radiators, Heater cores (French), prone to leaks
TRW Power steering pumps
Teves Rear disc brakes (GTIs, GLIs, Corrado)
Note: ATE = Albert Teves, div IT+T
VDO,MotoMeter Gauges
Wahler Thermostats
 
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