4KE 121 251 B
Radiator – 4KE 121 251 B
Radiator for the Audi 4K series (A6 / e-tron) platform, OE number 4KE 121 251 B. Main group 121 sub-group 251 identifies this as a radiator. Revision index B. Cooling capacity and mounting differ between engine variants on the same platform — confirm against your engine code before ordering.
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Technical specifications
| Part Number | 4KE 121 251 B |
| SKU | AUD-4KE121251B |
| Brand | |
| Category | Radiators |
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3–5 business days. Free on orders over $150.
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Order before 2 PM for next business day delivery.
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Return unused parts within 30 days for a full refund.
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Customer reviews
Verified feedback from Audi owners and independent workshops.
4.0
3 reviews
Thomas Lindqvist
July 23, 2026
Holds pressure beautifully
Fitted to my 2016 A8 D4. The core is thicker than the unit it replaced and the fin density is noticeably higher. Front end off, old one out, this one in over a long Saturday. Result is the gauge sits dead centre now even in traffic on a hot day. Exactly what I needed.
Talia Sorensen
December 14, 2025
Temps back to normal
Replacement for my 2011 A8 D4 3.0 TDI V6. The core is thicker than the unit it replaced and the fin density is noticeably higher. The transmission cooler lines threaded straight in with no adapters. Result is no more creeping temperature when towing. Will be back for the other side.
Daniel Weiss
November 25, 2025
Works, but watch the seams
Bought for a 2021 Q5 FY. 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 gauge sits dead centre now even in traffic on a hot day. Worth buying, just go in with your eyes open.