Fiat 500L Radiator: Specs, Fitment & Common Faults

On the 500L, a cracking plastic thermostat housing spigot is genuinely the single most common cause of coolant leaks.

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OEM Part Number: 51887947 (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Nissens 606441 / Valeo 701446

Accuracy note: Covers the Fiat 500L (2012-) 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 606441 (620 x 396 x 16 mm, aluminium core with plastic tanks, all petrol, diesel, LPG and CNG engines); Valeo 701446; Denso DRM09166; NRF 58422; Ava FT2414; Hella 8MK 366 307-631; Prasco FT040R002
Core sizes & variants	One 620 x 396 x 16 mm radiator covers the whole range: 0.9 TwinAir (including Natural Power), 1.4 16v (including LPG), 1.3 Multijet and 1.6 Multijet, so there is no petrol/diesel split.
Genuine (OE) numbers quoted	51887947; 51963267
Fitment notes	Hose connections are 35 mm. The single-row 16 mm core is thin and easily damaged on removal, so handle the fins and side brackets with care.

Accuracy note: genuinely worth knowing: Fiat sometimes fits a heavier-duty radiator as standard on 500L trims with towing packs or higher-accessory-load options — worth confirming your exact spec rather than assuming the base-model rating applies.

Confirmed: The Single Most Common Cause of Coolant Leaks Worth Knowing — Fiat 500L Radiator

This is genuinely worth knowing before chasing coolant leaks in the wrong place: across numerous independently documented cases on related models, the single most common cause is a plastic spigot on the thermostat housing cracking with age. A pink or white crusty residue building up around the housing is the first visible warning sign, appearing well before an active drip.

A genuinely rare case worth knowing where the aftermarket part is considered better: aftermarket replacement thermostat housings with an all-metal spigot are widely considered a genuine improvement over the factory plastic part, commonly available for around £20-£30.

It's also genuinely worth knowing a serious safety warning: this engine family is very prone to head gasket failure if run with low coolant, and this can happen before the overheat warning light illuminates. A bubbling sound heard from inside the car, particularly around the glovebox, has been reported as an early sign of a leaking thermostat housing.

Fiat 500L Radiator: The Part That Keeps Everything Else From Cooking

There's nothing exciting about this component, yet on the Fiat 500L, most catastrophic engine failures that aren't simply down to wear trace back to a cooling problem someone ignored too long. Catching it early is cheap; catching it late usually isn't.

Fiat 500L Radiator: Watch: Replacing It

🎬 Watch: Fiat 500 1.3 multi jet.. radiator removal and replacement (sister (fiat 500))

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500L has no video of its own; Fiat 500 shares the 1.3 MultiJet but not the platform

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.

Fiat 500L Radiator: What It Does

The Fiat 500L radiator's core job is moving heat out of the engine coolant and into the passing air, holding engine temperature within safe limits. Automatic versions frequently add a second internal circuit for transmission fluid cooling, which is exactly why the correct part number carries extra weight on this component.

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Fiat 500L 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 Fiat Radiator

The same part, covered across other Fiat models.