do88 Auxiliary Radiators (Pair) – Toyota GR Supra (A90) / BMW M240i / M340i / M440i / Z4 M40i (B58)

OVERVIEW

The B58 Gen 2 engine cooling system uses auxiliary radiators mounted ahead of each front wheel alongside the main radiator. Tuned cars make much more heat than the stock package was designed for, and the auxiliary radiators are an easy place to add capacity. The do88 WC-410 replaces both with all-aluminum radiators that have a larger 40 mm two-row core and hold more coolant than stock.

They are drop-in replacements for both the left and right side, with TIG-welded tanks, CNC-machined brackets and OE-style quick-connect fittings, and the factory rock guards transfer over. do88 sells them as a pair because upgrading only one side does little.

SPECS

• All-aluminum construction with TIG-welded end tanks
• Two-row core, 40 mm thick; larger core volume and coolant capacity than OE
• CNC-machined mounting brackets
• OE-style quick-connect inlet and outlet fittings
• Drop-in for left and right sides; accepts the OE rock guard
• Replaces OE 17118672237 (BMW), 16400-WAA04 (Toyota)

PARTS INCLUDED

• 2 × do88 performance auxiliary radiators (left and right)

TECH RESOURCES

• Required extras: engine coolant to prefill the radiators and top up the expansion tank.
• BMW fitment check: fits only BMW models with the factory right-side remote radiator 17118672237, included with the M Technology Package (option 33T). The GR Supra is not affected.
• Installation instructions (do88): WC-410 G-series / Supra auxiliary radiator installation instructions (PDF)
• Installation notes: remove the front wheels and inner wheel arches. Smooth the guard edges and transfer the OE guard, pinch and disconnect the hoses, drain, unscrew the top mount (T45) and tilt the radiator out. Prefill the do88 radiator, refit, and repeat on the other side.
• Bleeding: bleed with the car on the ground using the factory service routine (the engine revs on its own for about 11 minutes); let it cool before checking the expansion tank.
• Instructions are shot on a GR Supra; panel removal differs on the BMW models.
• Price is for the item only; labor is not included.

PART NUMBER

• WC-410 — do88 Auxiliary Radiator, BMW G-Series / Toyota GR Supra A90, pair

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