Honda Civic Radiator: Specs, Fitment & Common Faults

A genuinely important warning: using the wrong coolant type can cause real corrosion — plus a genuinely tricky DIY trap where the heater pipe can feel seated in the thermostat housing when it isn't.

Illustration for editorial purposes

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OEM Part Number: 19010R1AA02 (as quoted in catalogue listings — confirm via VIN) — aftermarket radiators Denso DRM40042 / NRF 58537

Accuracy note: Covers the Honda Civic (2012-2017) 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)	Denso DRM40042; NRF 58537; Ava HD2296; Van Wezel 25002701; AKS Dasis 100081N; Kale 347550. Denso DRM40043; NRF 59240; AKS Dasis 100083N. Denso DRM40041
Core sizes & variants	Three distinct cores: the 1.4 petrol takes the smallest 325 x 656 mm radiator, the 1.8 petrol a 375 x 678 mm core and the 2.2 diesel a thicker 375 x 733 x 28 mm core. The 1.8 part is listed for manual gearboxes, so automatic cars should be checked against the VIN.
Genuine (OE) numbers quoted	1.8: 19010R1AA02; 19010R1AA52. 1.4: 19010R3RE01.
Fitment notes	The 1.8 radiator is supplied with seals but without the expansion tank

Accuracy note: genuinely worth knowing: radiator core size and construction can differ between petrol and diesel Civic engines, and again between manual and automatic gearboxes where the automatic needs an integrated oil cooler circuit — confirm your exact engine code and transmission before ordering.

A Genuinely Important Warning Worth Knowing About Coolant Type — Honda Civic Radiator

If you're topping up or refilling the cooling system, this is genuinely worth taking seriously: using the wrong type of coolant — not just mixing different brands, but genuinely the wrong chemical formulation for your specific engine — has been documented as a real, direct cause of internal corrosion. One documented case saw an OAT-type coolant used on an engine that expected a different formulation, causing corrosion that led to a genuine, persistent leak even after related components were replaced. Always confirm the correct coolant specification for your specific engine before topping up, rather than assuming any coolant labelled for the right colour or general purpose is genuinely compatible.

A genuinely specific, tricky DIY installation trap worth knowing about the thermostat housing: the heater pipe that connects into the housing has a small amount of natural play or give, and can feel seated when it genuinely isn't pushed in fully. One documented case saw a leak develop specifically at this junction after reassembly, traced to the pipe not being seated all the way in despite feeling secure — a genuinely easy mistake to make. If you're doing this job yourself, it's worth applying firm, sustained pressure (some have used string or a clamp to hold the pipe in place) while confirming it's genuinely fully seated, rather than assuming it's correctly positioned just because it feels stable.

It's also worth knowing that a combination of elevated idle speed and rapid overheating shortly after thermostat or housing work often points toward trapped air in the cooling system rather than a genuine new leak — thoroughly bleeding the system after any work in this area is worth doing carefully, since an air pocket can mimic several other more serious symptoms.

Honda Civic Radiator: The Part That Keeps Everything Else From Cooking

This isn't a part anyone gets excited about, but on the Honda Civic, 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.

Honda Civic Radiator: Watch: Replacing It

🎬 Watch: How to Replace the Radiator for Honda Civic 2006-2015

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US 9th-gen sedan; UK FK2 hatch front end differs slightly

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.

Honda Civic Radiator: What It Does

Keeping the Honda Civic'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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Honda Civic 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 Honda Radiator

The same part, covered across other Honda models.