This page lists 12 belt drive parts for the 2021 Audi S8, across 2 part types, covering the 4.0L V8 Turbocharged engine. Every part shows its brand, manufacturer part number and fitment notes.
The belt drive system on the 2021 Audi S8 spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys. All 12 listed parts are Belt (8 parts) and Idler Pulley (4 parts).
Every part on this page is matched to the 4.0L V8 Turbocharged — the only engine offered in the 2021 Audi S8.
The most listed brands for 2021 Audi S8 belt drive parts are CONTINENTAL (3 parts), DAYCO (3 parts) and GATES (2 parts), plus 4 more brands. Quality grades include Standard Replacement and Economy.
2 parts on this 2021 Audi S8 page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including DAYCO 5040430 (Belt) and DAYCO 5060353 (Belt). Click any part number to see every vehicle that part fits.
Belt
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL | 430K4MK | 🇺🇸 US 🇲🇽 MX | Mileage MakerSerpentine | View on Amazon |
| DAYCO | 5040430DR | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Drive Rite®Serpentine | View on Amazon |
| FVP | 430K4 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Multi V-BeltSerpentine | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular | 5040430 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | SerpentineTop Width: .54 In | View on Amazon |
| DAYCO Popular | 5060353 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | SerpentineTop Width: .82 In | View on Amazon |
| ACDELCO | 4K423 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| CONTINENTAL | 4040430 | 🇺🇸 US 🇲🇽 MX | Multi V-BeltSerpentine | View on Amazon |
| GATES | K040423 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Micro-V | View on Amazon |
This table covers the serpentine and accessory belts that drive the front accessories. Typical signs include squeal on cold start, cracks across the ribs, or glazing on the back of the belt. A new belt on a worn tensioner will squeal within weeks — spin the idlers by hand while the belt is off.
8 Belt parts are listed for the 2021 Audi S8, from DAYCO, CONTINENTAL, FVP and 2 other brands. DAYCO 5040430 carries the "Popular" badge.
In the Economy grade, CONTINENTAL, DAYCO and FVP supply 3 parts: the catalog's value-priced group. A representative part number is CONTINENTAL 430K4MK.
The Standard Replacement section lists 5 options from DAYCO, ACDELCO, CONTINENTAL and 1 other brand — built to original-equipment specification. DAYCO 5040430 is listed in this group.
Part numbers include DAYCO 5040430, CONTINENTAL 430K4MK and DAYCO 5040430DR, among others listed above.
Idler Pulley
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VAICO | V108921 | 🇺🇸 US 🇲🇽 MX | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL | 50099 | 🇺🇸 US 🇲🇽 MX | Smooth | View on Amazon |
| GATES | 36901 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Smooth | View on Amazon |
| LITENS | 900699A | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Smooth | View on Amazon |
This table covers the idler pulleys the belt wraps around. Typical signs include a chirp that follows engine speed, or a pulley that feels rough or has play. Replace a noisy idler with the belt — the labor is already paid for.
4 Idler Pulley parts are listed for the 2021 Audi S8, from VAICO, CONTINENTAL, GATES and 1 other brand.
Economy: 1 part, from VAICO. A representative part number is VAICO V108921.
The Standard Replacement section: 3 options from CONTINENTAL, GATES and LITENS. CONTINENTAL 50099 is listed in this group.
Listed part numbers: VAICO V108921, CONTINENTAL 50099 and GATES 36901, plus the other parts above.
Buying Belt Drive Parts for a 2021 Audi S8
On this vehicle, the belt drive system spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys.
- Confirm you have the 4.0L V8 Turbocharged engine — every part on this page is matched to it.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Belt and Idler Pulley .
Frequently Asked Questions
How many belt drive parts fit the 2021 Audi S8?
Our catalog currently lists 12 belt drive parts for the 2021 Audi S8 across 2 subcategories and 7 brands, covering the 4.0L V8 Turbocharged engine. Each part is matched to the engine(s) it fits.
What are the signs of belt drive problems on a 2021 Audi S8?
Common symptoms include squealing on cold start, a belt that shows cracking or glazing, or an accessory that slows under load. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Audi S8 was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Audi S8?
Every part on this page is matched to the 4.0L V8 Turbocharged engine. Then a new belt on a worn tensioner will squeal within weeks — check tensioner damping and idler bearings while the belt is off. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Audi S8
Belt Drive Parts for Other Audi S8 Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.