Mazda 3 Radiator: Specs, Fitment & Common Faults

On the Mazda 3, the coolant reservoir genuinely differs by turbo vs non-turbo and even build location — always verify against your VIN.

Illustration for editorial purposes

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OEM Part Number: confirm via VIN — radiators (aftermarket) Nissens 68555 / Valeo 701329

Accuracy note: Covers the Mazda 3 (BM 2013-2019) 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 68555 (375 x 728 x 16 mm, soldered aluminium core with plastic tanks, fits 1.5 Skyactiv-G 100 and 120 PS, 1.6 105 PS and 2.0 Skyactiv-G 120 and 165 PS, engine codes P5Y1, P5Y5, P5Y4, P5Z3, Z6Y1, Z6Y3, PEY7, PEX2, PEY5, PEXL); Valeo 701329; Denso DRM44042; NRF 550024; Van Wezel 27012703; Hella 8MK 366 308-661; Prasco MZ332R001. For the diesel: Nissens 68557 (375 x 728 x 26 mm, soldered aluminium core with plastic tanks, fits 2.2 Skyactiv-D 150 PS, engine codes SHY4 and SHY6); Denso DRM44049
Core sizes & variants	Petrol and diesel share the same 375 x 728 mm face but the diesel core is 26 mm deep against 16 mm for the petrols. Gearbox type does not change the part.
Genuine (OE) numbers quoted	PE2015200 (petrol); SH1215200; SH1215200A (diesel)
Fitment notes	Petrol radiator connections are 34 mm, diesel 33 mm; no seals listed on either.

Accuracy note: genuinely worth knowing: many 3 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.

A Genuinely Important Fitment Warning Worth Knowing Before Ordering — Mazda 3 Radiator

If you're replacing the coolant reservoir specifically, this is genuinely worth knowing: fitment is considerably more complex than it might first appear, with real differences depending on whether your engine is turbocharged or non-turbo, and even on which factory the car was built in. Always verify against your specific VIN and visually match the part before buying.

A genuinely specific diagnostic detail worth knowing if chasing a subtle thermostat housing leak: rather than an obvious crack across the housing itself, a failing gasket or seal commonly manifests as weeping specifically around one of the housing bolts — worth checking this precise spot closely before assuming the housing itself needs replacing.

It's also worth knowing that a coolant bypass pipe near the thermostat housing on some Mazda diesel engines has been documented deteriorating with age and heat cycles, worth checking if you have an older diesel model experiencing unexplained coolant loss.

Mazda 3 Radiator: The Part That Keeps Everything Else From Cooking

There's nothing exciting about this component, yet on the Mazda 3, 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.

Mazda 3 Radiator: Watch: Replacing It

🎬 Watch: How to Replace Radiator 2014-2018 Mazda 3

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1A Auto; diesel alt https://www.youtube.com/watch?v=M-ehJCh8yQw (2.2D)

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.

Mazda 3 Radiator: What It Does

The Mazda 3 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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Mazda 3 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 Mazda Radiator

The same part, covered across other Mazda models.