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Audi A4 Cooling Expansion Tank Parts

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Expansion Tank Cap

ES#3672033 - 3C0121321 - Expansion Tank Cap - Keep proper pressure in your coolant system - Stant - Audi Volkswagen Porsche

Keep proper pressure in your coolant system Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Stant - Corporate Logo
ES#:
3672033
Mfg#:
3C0121321
Back Ordered
$5.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Replacement Kit W/ R8 Coolant Cap

ES#2598445 - 8D0121403LR8KT - Expansion Tank Replacement Kit W/ R8 Coolant Cap - Install a brand new expansion tank with a new R8 polished aluminum cap and hardware - Assembled By ECS - Audi Volkswagen

Install a brand new expansion tank with a new R8 polished aluminum cap and hardware 10X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
From VIN 8D-W-007800, split is in the 1998 model year

Brand:
Assembled By ECS - Corporate Logo
ES#:
2598445
Mfg#:
8D0121403LR8KT
Ships in 3 Business Days
$345.99

This product was last offered at the strikethrough price on
10-26-2026

$341.99 USD
Free Shipping
This product is lifetime replacement eligible Lifetime Replacement

Coolant T Connector

ES#4899607 - N90692901 - Coolant T Connector - Connects to the lower radiator hose - Rein - Audi Volkswagen

Connects to the lower radiator hose 2X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
We Price Match - Give Us A Call or Chat!
Connects lower radiator hose to the coolant expansion tank hose and water pump hose

Brand:
Rein - Corporate Logo
ES#:
4899607
Mfg#:
N90692901
Ships in 4 Business Days
$9.99 USD
Free Shipping
on orders $49 and up

Engine Coolant Reservoir Cap

ES#5528431 - 4M0121321Q - Engine Coolant Reservoir Cap - Keep proper pressure in your coolant system - URO - Audi

Keep proper pressure in your coolant system 2X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
URO - Corporate Logo
ES#:
5528431
Mfg#:
4M0121321Q
Ships in 2 Business Days
$26.99 USD
Free Shipping
on orders $49 and up

VW | Expansion Tank, coolant

ES#4864980 - 8K0121403AC - VW | Expansion Tank, coolant - Vaico - Audi

Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
We Price Match - Give Us A Call or Chat!

Brand:
Vaico - Corporate Logo
ES#:
4864980
Mfg#:
8K0121403AC
Ships in 2 Business Days
$53.99

This product was last offered at the strikethrough price on
05-07-2026

$51.99 USD
Free Shipping
on orders $49 and up

Expansion Tank Replacement Kit W/ R8 Coolant Cap

ES#2649684 - 8E0121403AKT3 - Expansion Tank Replacement Kit W/ R8 Coolant Cap - Install a brand new expansion tank with a new R8 polished aluminum cap and hardware - Assembled By ECS - Audi

Install a brand new expansion tank with a new R8 polished aluminum cap and hardware 10X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Assembled By ECS - Corporate Logo
ES#:
2649684
Mfg#:
8E0121403AKT3
Ships in 1-2 days
$346.44

This product was last offered at the strikethrough price on
10-26-2026

$341.61 USD
Free Shipping
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Replacement Kit W/ R8 Coolant Cap

ES#2631365 - 8E0121403KT5 - Expansion Tank Replacement Kit W/ R8 Coolant Cap - Install a brand new expansion tank with a new R8 polished aluminum cap and hardware - Assembled By ECS - Audi

Install a brand new expansion tank with a new R8 polished aluminum cap and hardware 10X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Assembled By ECS - Corporate Logo
ES#:
2631365
Mfg#:
8E0121403KT5
Ships in 3 Business Days
$331.99

This product was last offered at the strikethrough price on
10-26-2026

$326.99 USD
Free Shipping
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Replacement Kit

ES#2678371 - 8K0121405NKT2 - Expansion Tank Replacement Kit - Install a brand new expansion tank with a new cap and hardware - Genuine Volkswagen Audi - Audi

Install a brand new expansion tank with a new cap and hardware Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Genuine Volkswagen Audi - Corporate Logo
ES#:
2678371
Mfg#:
8K0121405NKT2
Ships in 1-2 days
$236.99

This product was last offered at the strikethrough price on
08-31-2026

$223.99 USD
Free Shipping
This product is lifetime replacement eligible Lifetime Replacement

Coolant Expansion Tank

Clean up your engine bay or replaced your cracked unit with a new coolant expansion tank Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
For Vehicles with DPAA Engine Code Only

Brand:
Genuine Volkswagen Audi - Corporate Logo
ES#:
4307416
Mfg#:
8W0121405K
Ships in 1-2 days
13% off MSRP

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$76.99

This product was last offered at the strikethrough price on
08-31-2026

$66.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Cap

Plastic pressure cap for expansion tank Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Hudson - Corporate Logo
ES#:
3463373
Mfg#:
8E0121321
Ships in 1-2 days
$5.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Replacement Kit

ES#3969909 - 8w0121405gKT1 - Expansion Tank Replacement Kit - Install a brand new expansion tank with a new cap and hardware - Genuine Volkswagen Audi - Audi

Install a brand new expansion tank with a new cap and hardware Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
Fits from production date 1/14/2019

Brand:
Genuine Volkswagen Audi - Corporate Logo
ES#:
3969909
Mfg#:
8W0121405GKT1
Ships in 6 Business Days
$252.99

This product was last offered at the strikethrough price on
10-26-2026

$248.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Expansion Tank Replacement Kit

ES#3969907 - 8w0121405eKT - Expansion Tank Replacement Kit - Install a brand new expansion tank with a new cap and hardware - Genuine Volkswagen Audi - Audi

Install a brand new expansion tank with a new cap and hardware Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
Fits up to production date 11/13/2017

Brand:
Genuine Volkswagen Audi - Corporate Logo
ES#:
3969907
Mfg#:
8W0121405EKT
Ships in 6 Business Days
$252.99

This product was last offered at the strikethrough price on
10-26-2026

$248.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Coolant Expansion Tank

ES#4901309 - 8K0121403AC - Coolant Expansion Tank - Plastic reservoir for the coolant system - Meyle - Audi

Plastic reservoir for the coolant system 5X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
We Price Match - Give Us A Call or Chat!

Brand:
Meyle - Corporate Logo
ES#:
4901309
Mfg#:
8K0121403AC
Ships on Nov 19, 2026
$34.99 USD
Free Shipping
on orders $49 and up
This product is lifetime replacement eligible Lifetime Replacement

Coolant Expansion Tank

Plastic reservoir for the coolant system 10X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply

Brand:
Bremmen Parts - Corporate Logo
ES#:
5397089
Mfg#:
8K0121403Q
Special Order: No Guaranteed ETA
ON SALE! SAVE 12%
$30.99

This product was last offered at the strikethrough price on
05-02-2026

$27.19 USD
Free Shipping
on orders $49 and up

Expansion Tank Replacement Kit

ES#2586882 - 8D0121403DKT - Expansion Tank Replacement Kit - Install a brand new expansion tank with a new cap and hardware - Assembled By ECS - Audi

Install a brand new expansion tank with a new cap and hardware 10X Entries Into Our F80 M3 Sweepstakes Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
Up to VIN 8D-W-007799, split is in the 1998 model year

Brand:
Assembled By ECS - Corporate Logo
ES#:
2586882
Mfg#:
8D0121403DKT
Back Ordered
$59.99

This product was last offered at the strikethrough price on
09-03-2026

$57.99 USD
Free Shipping
This product is lifetime replacement eligible Lifetime Replacement

Coolant Expansion Tank

ES#5492873 - 8W0121405L - Coolant Expansion Tank - Coolant expansion tank to cure mysterious coolant loss, resolve false dashboard warnings, and restore reliable engine cooling and aesthetics to your B9 chassis Audi. - Febi - Audi

Coolant expansion tank to cure mysterious coolant loss, resolve false dashboard warnings, and restore reliable engine cooling and aesthetics to your B9 chassis Audi. Earn 5% back in ECS Rewards on orders placed 10/26/26 - 10/31/26. Redeem 11/26/26 - 12/1/26. Terms & conditions apply
For Vehicles with CYMC Engine Code Only

Brand:
Febi - Corporate Logo
ES#:
5492873
Mfg#:
8W0121405L
Special Order: No Guaranteed ETA
$78.99 USD
Free Shipping
on orders $49 and up

More About Cooling Expansion Tank Parts

A common source of overheating problems is a broken or leaking coolant expansion tank. Replace it with an OEM coolant expansion tank or quality aftermarket expansion tank to prevent future woes.

Let us help you find the parts that fit your Audi

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Manufacturer names and/or part numbers are used only for identification purposes.

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