Vauxhall Grandland X Radiator: Specs, Fitment & Common Faults

A failing expansion tank cap seal is a well-documented, often-overlooked cause of coolant loss on the Grandland X — worth checking first.

Illustration for editorial purposes

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OEM Part Number: 3644889 (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Nissens 607100 / Valeo 701109

Accuracy note: Covers the Vauxhall Grandland X (2017-) 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)	Valeo 701109 (500 x 500 x 50 mm, aluminium core with plastic tanks, fits 1.2 Turbo 130, 1.5 Turbo D 102/130, 1.6 Turbo 150/180, 1.6 Turbo D 120, 1.6 Turbo Hybrid 224, 1.6 Hybrid4 300 and 2.0 D 177); Nissens 607100; Van Wezel 37012732; AKS Dasis 150159N; Wilmink WG2301750.
Core sizes & variants	One 500 x 500 mm radiator with a deep 50 mm core is listed for every Grandland X engine, petrol, diesel and plug-in hybrid alike.
Genuine (OE) numbers quoted	3644889; 9815574380
Fitment notes	Inlet and outlet are 35 mm

Accuracy note: genuinely worth knowing: coolant capacity and radiator sizing on the Grandland X tend to track engine displacement and power output closely — a part correct for a smaller-engined version of the same model can undersize the cooling for a larger-engined one.

A Genuinely Overlooked Cause of Coolant Loss Worth Checking First — Vauxhall Grandland X Radiator

If coolant keeps disappearing with no visible leak underneath the car, it's genuinely worth checking the expansion tank cap itself before assuming a more expensive fault. A failing seal in the cap is a well-documented, commonly overlooked cause of coolant loss and a hissing sound once the engine's hot — and it's often overlooked in favour of investigating the thermostat or head gasket first, even though it's a genuinely cheap part to simply replace and rule out.

A genuinely useful filling technique: air pockets trapped in the cooling system during a refill are a common, underappreciated cause of overheating symptoms and a coolant level that seems to disappear — filling too quickly is the usual cause. Adding coolant slowly, almost dribbling it in, gives trapped air a proper chance to escape rather than getting sealed into a pocket that later causes symptoms that look exactly like a leak or failing thermostat.

Vauxhall Grandland X Radiator: The Part That Keeps Everything Else From Cooking

Unglamorous as it is, the Vauxhall Grandland X'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.

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.

Vauxhall Grandland X Radiator: Watch: Replacing It

🎬 Watch: Peugeot 308 radiator replacement without removing bumper T7 (sister (Peugeot 308))

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closest video found; the radiator comes out the same way once the front panel and fan are off

Vauxhall Grandland X Radiator reference plate

Vauxhall Grandland X Radiator: What It Does

On the Vauxhall Grandland X, 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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Vauxhall Grandland X 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 Vauxhall Radiator

The same part, covered across other Vauxhall models.