Radiator – 1K0 121 251 AK
Radiator for the VW Group PQ35 (Golf V / A3 8P / TT) platform, OE number 1K0 121 251 AK. Main group 121 sub-group 251 identifies this as a radiator. Revision index AK. 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 | 1K0 121 251 AK |
| SKU | AUD-1K0121251AK |
| Brand | |
| Category | Radiators |
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3–5 business days. Free on orders over $150.
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Customer reviews
Verified feedback from Audi owners and independent workshops.
4.1
8 reviews
Viktor Sorensen
August 7, 2026
Temps back to normal
Bought for a 2014 Q7 4L. The plastic feels substantial rather than the brittle stuff that cracks at the neck. I bled it through the proper procedure and it has held level ever since. Result is no more creeping temperature when towing. Happy to recommend it.
Jonas Zimmer
August 7, 2026
Straight swap
Fitted to my 2016 A1 8X. The transmission cooler lines threaded straight in with no adapters. The end tanks are properly crimped with clean seams all the way round. Result is intake temps dropped noticeably on a long motorway pull. Would order again without hesitation.
Hugo Fitzgerald
August 4, 2026
Better core than the original
Fitted to my 2015 A5 8T. 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 no more creeping temperature when towing. Exactly what I needed.
Camille Vogel
February 6, 2026
Holds pressure beautifully
My A3 8V needed this doing at 155k miles. The plastic feels substantial rather than the brittle stuff that cracks at the neck. I bled it through the proper procedure and it has held level ever since. Result is the gauge sits dead centre now even in traffic on a hot day. Delivery was quick too.
Bastian Ferreira
October 30, 2025
Good rad, mounting tabs tight
Replacement for my 2006 A4 B7 2.5 TFSI. 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.
Niall Silva
May 25, 2025
Solved my overheating
Ordered this for my A5 8T after the original gave up at 94k. The plastic feels substantial rather than the brittle stuff that cracks at the neck. I bled it through the proper procedure and it has held level ever since. Result is the coolant level has not moved in four months.
Yusuf Petrov
March 27, 2025
Works, but watch the seams
Ordered this for my A6 C7 after the original gave up at 55k. I flushed the system properly and refilled with the correct G13 before bleeding. 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. Fine for the money, with that one caveat.
Martin Vance
February 26, 2025
Perfect fit, no modification
Second one of these I have bought, this time for the TT 8J. I flushed the system properly and refilled with the correct G13 before bleeding. The end tanks are properly crimped with clean seams all the way round. Result is the coolant level has not moved in four months.