Lexus NX Radiator: Specs, Fitment & Common Faults

On the NX, this hybrid genuinely has a separate inverter coolant system, and if it detects overheating, the car likely won't let you continue driving at all — a protective measure that may mean towing.

Illustration for editorial purposes

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OEM Part Number: 1640036090 (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Valeo 701323 / Denso DRM50151

Accuracy note: Covers the Lexus NX (2014-2021) as listed in the UK aftermarket catalogues. Radiators are sold by engine, gearbox and air-conditioning fitment, and one model usually has two or three different cores — a thicker core for diesels and automatics, a thinner one for small petrols — with different hose positions, so a radiator for the wrong engine will not connect up. The references below are UK aftermarket listings whose fitment lists name this generation, labelled by brand with the core size in mm; genuine numbers are those quoted against the listing. Check your engine code and whether the car has air conditioning against your VIN, and replace the coolant and bleed the system after fitting.

Radiators (aftermarket)	Denso DRM50151 (674 x 415 x 27 mm, fits NX 300h front-drive and AWD, also RAV4 IV 2.5 Hybrid); NRF 550420 (675 x 411 x 26 mm, aluminium, soldered core); Valeo 701323; JDEUS M-0281150; Wilmink WG2646651
Core sizes & variants	One radiator covers both front-drive and AWD NX 300h models and is shared with the RAV4 Hybrid. The 2.0 turbo NX 200t/300 (8AR-FTS) is not on either fit list and takes a different radiator.
Genuine (OE) numbers quoted	1640036090
Fitment notes	the Denso unit is the OE supplier's own aftermarket part, which is the safest match for the hybrid cooling circuit.

Accuracy note: genuinely worth knowing: radiator core size and construction can differ between petrol and diesel NX engines, and again between manual and automatic gearboxes where the automatic needs an integrated oil cooler circuit — confirm your exact engine code and transmission before ordering.

Lexus NX Radiator: The Part That Keeps Everything Else From Cooking

Nothing about this component is glamorous, but on the Lexus NX, almost every serious engine failure that isn't wear-related traces back to a cooling system problem left unaddressed. Catching the early signs here is genuinely cheap insurance against a much bigger bill.

Before you buy: radiator size and design vary significantly by engine size, transmission type, and whether your car has air conditioning. Always confirm against your VIN before ordering.

Lexus NX Radiator: What It Does

The Lexus NX's radiator transfers heat from the engine coolant to the surrounding air, keeping engine temperature within a safe operating range. On automatic versions, it often also cools transmission fluid through a separate internal circuit — one more reason the correct part number matters so much here.

Lexus NX Radiator: Watch: Replacing It

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A Genuinely Important Finding Worth Knowing About This Hybrid's Cooling System — Lexus NX Radiator

This is genuinely important to understand: there's a genuinely separate inverter coolant system, distinct from the normal engine cooling system, specifically to keep the power electronics at a safe temperature. It's also genuinely important to know that if the hybrid system detects an overheat, it will likely not allow you to continue driving at all, as a protective measure specifically for the transmission, electric motors, and high-voltage battery — the car may genuinely need to be towed rather than driven even a short distance.

A genuinely useful, emergency-only tip worth knowing: if the inverter coolant level specifically is found low in a genuine emergency, temporarily topping it off with plain water rather than proper coolant can get you safely to your destination, with a proper inspection and refill to follow once there.

It's also genuinely worth knowing that diagnosing the exact cause of a hybrid overheat warning is genuinely difficult without a proper scan tool, since retrieving the actual fault codes is necessary to identify which specific component has failed. It's also worth always properly diluting coolant concentrate with distilled water per the bottle's instructions, since undiluted coolant can itself cause overheating.

Lexus NX Radiator: Faults, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Radiator Guide for the three common failure modes, confirming fitment against your VIN, and OEM vs aftermarket guidance.

More Lexus Radiator

The same part, covered across other Lexus models.