Audi A3 S Line Rear Bumper Diffuser 2013 to 2016 8V5807521

Part number 8V5807521. We take parts off vehicles every week, and this page is updated with a link straight to the part as soon as another one arrives.

OUT OF STOCK

In the meantime you can see every Audi part we have in stock, or you can send us a message and we will tell you the day one comes in.

Notify me when this part is back in stock

Leave your email address and we will write to you the day part number 8V5807521 comes in. We use your address for that message only.

About part number 8V5807521

A rear bumper diffuser is a bodywork component fitted to the lower section of the rear bumper. It forms part of the exterior trim and aerodynamic system, directing airflow underneath the rear of the vehicle to reduce drag and improve stability at higher speeds. When the diffuser is intact and fitted correctly, the driver notices a neat, complete appearance at the back of the car with secure trim that does not rattle or loosen while driving.

To ensure this is the correct part, you must match the part number 8V5807521 exactly with the number stamped on your original item. On a trim piece of this type, the part number is usually moulded or stamped directly into the plastic on the inner or rear surface. Matching this exact part number is the only way to confirm correct fitment, as physical shape and mounting clip locations vary between different trim levels.

When replacing a rear bumper diffuser, you often need replacement plastic fixing clips, screws, or mounting brackets, as the original fasteners frequently break or stretch during removal. Drivers usually replace a diffuser due to impact damage from low-level obstacles, reversing incidents, surface scratches, or cracked mounting tabs that prevent the panel from clipping securely into the bumper.

About this kind of part: bumper trims and diffusers

A bumper trim is one of the separate strips and panels that clip or screw onto a bumper cover rather than forming part of it: a lower blade, a diffuser insert at the rear, a corner section, a splitter under the front edge, or the finisher around a fog lamp. They are usually gloss black, textured black or a bright finish, and they carry most of the model's styling, so they change between trim levels and across a facelift while the bumper cover underneath them stays the same part.

Why people replace one

  • The trim has grounded on a kerb, a ramp or a speed hump, which is what happens to anything mounted below the bumper line.
  • A clip has snapped and the trim now stands away from the bumper at one end.
  • The gloss black finish has gone grey and dull, or the bright finish has lifted, and it cannot be brought back.
  • Stone chipping along the leading edge has broken through the finish.
  • The bumper cover has been replaced and the original trim was broken getting it off.

Fitting it

  • Most clip to the bumper cover from the front and are then secured by screws or plastic nuts reached from behind or underneath.
  • The clips are usually separate parts and are worth replacing rather than reusing, because they stretch once they have been off.
  • Work along the trim from one end rather than pulling in the middle, which is where a cold strip cracks.
  • Where the trim surrounds a fog lamp or a sensor, check the aperture lines up before everything is tightened.

Making sure it is the right one

  • Match the part number on the back. These parts carry the styling, so a trim from a different version of the same model will often clip on and still look wrong.
  • Check whether yours has openings for parking sensors. A trim with no openings cannot be used on a car that has them.
  • Compare the finish as well as the shape. The same trim is made in gloss black, in textured black and in a bright finish, and each is a separate number.
  • Count the clip positions and the screw points, and compare their spacing with the part you are taking off.

What to look for in the photographs

A Part number — Moulded into the back face, usually towards one end.
B Sensor openings — Openings for parking sensors, where the trim sits across a sensor line. Their presence or absence decides whether it fits your car.
C Clips and screw points — The clip seats and threaded points along the back. Count them and look for any that are broken out.
D Lower edge — The bottom face, which grounds on kerbs and ramps. Look along it rather than at it, because this is what a straight-on photograph flatters most.
E Finish — Gloss black, textured black or a bright finish. The finish is part of what you are matching, not a detail.
F End profile — The shape where the trim meets the bumper and the arch. This is what tells one side from the other and a facelift from the version before it.

This section describes bumper trims and diffusers parts in general. The numbers and the photographs above are this part.

Free next-day delivery in the United Kingdom Sent with DPD on a tracked, next-day service. Most mainland addresses are next day; the Highlands and Islands, Northern Ireland, the Channel Islands and the Isle of Man can take a day longer.

Returns Thirty days to change your mind, and we pay the return postage in the United Kingdom and Germany.

Trade and VAT C.E.J Haime Group Limited is VAT registered in England and Wales, and every order comes with a full VAT invoice.

Not sure it is the right part? Send us your registration or VIN and we will check this part number against your own vehicle before you buy.

Ask us about this part

Other part numbers on this site

See every Audi part number we list · All part numbers · Everything in stock now