N54/N55 Billet Aluminum Radiator (17117547059)

PRE-ORDER: first batch ships January 2027. Order now to reserve yours from the first run.

The N54/N55 radiator core isn't what fails. The plastic end tanks are. They crack with age and heat cycles, usually with no warning.

We start with an OEM core (Mahle-Behr or Valeo), cut off the plastic tanks, and weld on end tanks CNC-machined from billet 6061-T6 aluminum. Same cooling capacity BMW designed the car around, with the weak point gone. Backed by a lifetime warranty.

Replaces OEM part numbers: 17117547059, 17117558480, 17117788903. One radiator fits automatic, DCT and manual cars.

Why not a thicker radiator?

The N54 and N55 run a map-controlled electronic thermostat calibrated to the factory radiator's capacity. A thicker aftermarket core can overcool the engine, especially in cold climates, and the thermostat can't be retuned to compensate. On these engines the radiator is rarely the limit; if you need lower temps, an oil cooler (and intercooler on turbo cars) is the real fix. Read how we got here.

• OEM core (Mahle-Behr or Valeo): factory cooling capacity and thermostat behavior
• Billet 6061-T6 aluminum end tanks, CNC-machined and welded to the core. Machined, not folded from sheet
• OEM-matched internal tank geometry: coolant flows through the core exactly as the factory tank directs it
• Machined 6061-T6 inlet and outlet necks
• Bolt-on 6061-T6 mounting brackets at the OEM mounting points
• Lifetime warranty on the end tanks, welds, necks and brackets

Install note: transfer the fitting from your old radiator. Automatic / DCT cars use control sleeve 17117521781; manual cars use plug 17117529497. Not included.

Fitment (N54 / N55):

• E90 / E91 / E92 / E93 335i, 335is, 335xi
• E82 / E88 135i, 135is, 1M
• E89 Z4 sDrive35i, sDrive35is
• E84 X1 xDrive35i

Lifetime warranty

If an end tank, weld, neck or bracket we made ever cracks or leaks, we'll repair or replace the radiator for as long as you own the car. Covers the original purchaser. Does not cover the core, impact or accident damage, improper installation, or modification. Email yang@maxqstore.com with your order number and photos to start a claim.

Pre-orders can be cancelled for a full refund until production of your unit starts. Once production has started, the order cannot be cancelled. See our Refund Policy.