Kia Niro Radiator: Specs, Fitment & Common Faults

On the Niro, a radiator, thermostat, and housing were all replaced on a related model, yet the coolant smell genuinely persisted, pointing toward the heater core.

Illustration for editorial purposes

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OEM Part Number: 25310G2000 (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Nissens 606607 / Valeo 701321

Accuracy note: Covers the Kia Niro (2016-2022) 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)	Nissens 606607 (610 x 398 x 16 mm, aluminium core with plastic tanks, fits 1.6 GDI Hybrid and Plug-in Hybrid 104 kW G4LE); Valeo 701321; NRF 550164; Van Wezel 82012720; Ava KA2331; Hella 8MK 366 303-541; Prasco HN150R001.
Core sizes & variants	One engine radiator covers both the self-charging hybrid and the plug-in hybrid, and the same part fits the Hyundai Ioniq AE and the hybrid Ceed and XCeed. The hybrid system has a separate low-temperature cooler for the drive battery and inverter (Nissens 606608 family) that is not the engine radiator.
Genuine (OE) numbers quoted	25310G2000
Fitment notes	Supplied with gaskets and seals, with 33 mm inlet and outlet connections. The thin 16 mm core is correct for this car and should not be swapped for a thicker unit.

Accuracy note: genuinely worth knowing: automatic gearbox Niros typically need a radiator with a built-in transmission oil cooler that manual versions don't have — ordering the manual-spec part for an automatic car will fit, but won't cool the gearbox oil properly.

A Genuinely Honest Account Worth Knowing If the Smell Persists — Kia Niro Radiator

This is genuinely worth knowing if you're chasing a coolant smell that won't go away: one documented case on a related model saw the radiator, thermostat, and thermostat housing all replaced in turn, with the car not overheating, yet the smell of coolant persisted after driving. If you've replaced the obvious components and the smell remains, it's genuinely worth having the heater core checked specifically.

A genuinely useful diagnostic distinction worth knowing: a leak from the water pump's weep hole tends to show ongoing, visible wetness, whereas a leak from a plastic radiator tank seal can dry up quickly once system pressure is released, making it considerably harder to spot on a static inspection.

It's also worth knowing that the thermostat housing sits toward the front of the engine, higher up than where normal AC condensation would appear.

Kia Niro Radiator: The Part That Keeps Everything Else From Cooking

Unglamorous as it is, the Kia Niro's cooling system sits behind nearly every serious engine failure that isn't just ordinary wear — and one that went unaddressed for too long. Noticing early warning signs here is a small cost against a potentially very large one.

Kia Niro Radiator: Watch: Replacing It

🎬 Watch: RADIATOR REPLACEMENT ON KIA SPORTAGE 2017-2022 @WrenchingRyan (sister (kia sportage))

Watch on YouTube ↗

No Niro or Hyundai Ioniq rad video found; Sportage is a different platform, so treat as nearest-Kia only

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.

Kia Niro Radiator: What It Does

On the Kia Niro, engine coolant sheds its heat into the passing air via the radiator, which is what keeps engine temperature in a safe working range. On automatics, it frequently pulls double duty cooling the transmission fluid through its own internal circuit — a detail that makes getting the exact part number right especially important.

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Kia Niro 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 Kia Radiator

The same part, covered across other Kia models.