Volkswagen Passat Radiator: Specs, Fitment & Common Faults

If your Passat has an EA888 TSI engine, VW has legally admitted to using "inferior thermoplastic materials" in the water pump housing — a real class-action settlement covers this.

Illustration for editorial purposes

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OEM Part Number: 5Q0121253J (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Nissens 606644 additional radiator / Mahle CR 1966 000P

Accuracy note: Covers the Volkswagen Passat (B8 2014-) 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 606644 additional radiator (195 x 186 x 26 mm, aluminium core, plastic tanks, 20 mm connections, supplied with seals, fits 2.0 TDI 4Motion 240 PS CUAA and 2.0 TSI 4Motion 272/280 PS CJXA, DNFE, DNUA); NRF 550287; Mahle CR 1966 000P; Van Wezel 58012720; Hella 8MK 366 307-681; Ava VN2460; Kamoka 7705228
Core sizes & variants	The small 195 x 186 mm unit is the supplementary radiator fitted to the high-output 4Motion B8s (bi-turbo 240 PS TDI and 272/280 PS TSI).
Genuine (OE) numbers quoted	Additional radiator: 5Q0121253J
Fitment notes	Order the main radiator against the VIN and quote the suffix on the old tank's 5Q0121251 label, as the MQB range uses several core lengths and thicknesses depending on engine, gearbox and whether a second (additional) radiator is fitted.

Accuracy note: genuinely worth knowing: many Passat radiators are engine-code specific rather than universal across the range — the engine code is usually stamped on the block or listed on the VIN plate, and it's the most reliable way to confirm fitment.

Confirmed: A Genuinely Serious, Class-Action-Level Design Flaw on TSI Engines — Volkswagen Passat Radiator

If your car has a TSI turbo petrol engine (particularly the EA888 family used across much of VW's range from around 2015 onward), this is genuinely the single most important thing to know before anything else on this page. The water pump and thermostat are combined into one integrated plastic housing, and this plastic becomes brittle and develops hairline cracks after thousands of ordinary heat cycles — leading to a coolant leak that's often difficult to spot at first. This isn't a minor manufacturing quirk: VW has confirmed through legal documents that "inferior thermoplastic materials were used" in these water pump components, and the issue has been the subject of multiple class-action lawsuits.

What VW's settlement genuinely offers: a Technical Service Bulletin extends the warranty on this specific part to 8 years/80,000 miles, and the class-action settlement goes further still — up to 10 years/100,000 miles warranty, reimbursement of qualifying repairs, and crucially, reimbursement of up to £3,300 for consequential damage if the leak went undiagnosed long enough to damage the turbocharger or EGR system. If you've paid for this repair or suffered related engine damage, it's genuinely worth checking whether you qualify before assuming the cost is yours to bear.

Watch for a low coolant warning, a sweet smell in the engine bay (especially after motorway driving), or fault codes P00B7, P2681, P1889, or P0128 — any of these are worth investigating immediately rather than topping up and continuing, since this failure can escalate from a slow leak to sudden, severe overheating within minutes. If this does need replacing, the entire water pump and thermostat housing assembly must be replaced together — never just one part of it.

Volkswagen Passat Radiator: The Part That Keeps Everything Else From Cooking

This isn't a part anyone gets excited about, but on the Volkswagen Passat, overlooked cooling problems are responsible for most serious engine failures that aren't simple wear-and-tear. Catching the early symptoms is about the cheapest insurance available against a major bill later.

Volkswagen Passat Radiator: Watch: Replacing It

🎬 Watch: 2014 VOLKSWAGEN PASSAT RADIATOR REPLACEMENT (older gen)

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US NMS Passat, not B8; no B8 radiator video found

Volkswagen Passat Radiator reference plate

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.

Volkswagen Passat Radiator: What It Does

Keeping the Volkswagen Passat's engine temperature within safe limits comes down to the radiator's job of transferring heat from the coolant into the surrounding air. Automatic-gearbox versions often build in a second circuit for transmission fluid cooling too, which is exactly why fitting the wrong part number can cause two problems, not one.

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Volkswagen Passat 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 Volkswagen Radiator

The same part, covered across other Volkswagen models.