Radiator – 8W0 121 251 AA
Radiator for the Audi A4 (B9) / A5 / allroad platform, OE number 8W0 121 251 AA. Main group 121 sub-group 251 identifies this as a radiator. Revision index AA. Cooling capacity and mounting differ between engine variants on the same platform — confirm against your engine code before ordering.
Next-day dispatch
30-day returns
Secure checkout
Fitment checker
Confirm this part fits your specific Audi — including the engine code — before ordering.
Confirmed fitment
Technical specifications
| Part Number | 8W0 121 251 AA |
| SKU | AUD-8W0121251AA |
| Brand | |
| Category | Radiators |
Shipping & returns
Standard shipping
3–5 business days. Free on orders over $150.
Express delivery
Order before 2 PM for next business day delivery.
Easy returns
Return unused parts within 30 days for a full refund.
International
We ship worldwide. Duties may apply at destination.
Customer reviews
Verified feedback from Audi owners and independent workshops.
3.8
8 reviews
Greta Delgado
August 10, 2026
Solved my overheating
My A4 B7 needed this doing at 53k miles. The plastic feels substantial rather than the brittle stuff that cracks at the neck. I flushed the system properly and refilled with the correct G13 before bleeding. Result is the coolant level has not moved in four months.
Sofia Larsen
July 21, 2026
Holds pressure beautifully
Cross-referenced the OE number against my 2011 A3 8P before ordering. All the mounting points and hose stubs lined up without any persuasion. The end tanks are properly crimped with clean seams all the way round. Result is the coolant level has not moved in four months. Delivery was quick too.
Aisha Halvorsen
May 15, 2026
Fits, but budget a new fan shroud
Went on my A3 8P 3.0 TDI V6 at 150k miles. Front end off, old one out, this one in over a long Saturday. I pressure tested it to 1.4 bar before fitting and it held without a drop. On balance the gauge sits dead centre now even in traffic on a hot day. Worth buying, just go in with your eyes open.
Martin Bauer
May 6, 2026
Works, but watch the seams
Bought for a 2012 A6 C7. The transmission cooler lines threaded straight in with no adapters. A weep appeared at the end tank seam after a few heat cycles. That said, intake temps dropped noticeably on a long motorway pull. Worth buying, just go in with your eyes open.
Lukas Vogel
April 13, 2026
Works, but watch the seams (A5 8T)
Cross-referenced the OE number against my 2011 A5 8T before ordering. The transmission cooler lines threaded straight in with no adapters. A weep appeared at the end tank seam after a few heat cycles. That said, the coolant level has not moved in four months. Worth buying, just go in with your eyes open.
Jonas Marchetti
March 9, 2026
Works well, packaging was thin
Second one of these I have bought, this time for the A7 4G. I bled it through the proper procedure and it has held level ever since. The end tanks are properly crimped with clean seams all the way round. On balance intake temps dropped noticeably on a long motorway pull. Would still buy it again.
Diego Marchetti
June 8, 2025
Perfect fit, no modification
Fitted to my 2019 Q7 4M. The end tanks are properly crimped with clean seams all the way round. All the mounting points and hose stubs lined up without any persuasion. Result is intake temps dropped noticeably on a long motorway pull.
Claire Haugen
April 6, 2025
Temps back to normal
Went on my S3 8V 2.0 TFSI at 69k miles. All the mounting points and hose stubs lined up without any persuasion. The plastic feels substantial rather than the brittle stuff that cracks at the neck. Result is the gauge sits dead centre now even in traffic on a hot day.