Radiator: Guides by Make & Model

Cooling system design differs a lot between engines and transmissions — find your specific model below.

A Boring Part Until It Isn't

Nobody thinks about their cooling system until the temperature gauge starts climbing. Pick your make and model below for fitment specifics and the early warning signs worth knowing before that happens.

How It Actually Cools the Engine

Hot coolant leaves the engine and enters the radiator's inlet tank, then flows across a core made of narrow tubes lined with thin metal fins. As air passes over these fins — helped along by an electric fan at low speed, and by the car's own forward motion at higher speed — heat transfers from the coolant, through the tube walls, into the fins, and out into the passing air. The cooled coolant collects in the outlet tank and returns to the engine to pick up more heat, in a cycle that runs continuously from the moment the thermostat opens until the engine shuts off. A pressure cap keeps the system running above atmospheric pressure, which raises the coolant's boiling point and helps prevent it flashing to steam under hard use; when pressure exceeds the cap's rating, it vents into an overflow reservoir rather than letting the system fail catastrophically.

Modern Radiators Aren't Built Like Old Ones — and That Changes How You Should Treat Them

Older radiators used copper cores with soldered brass tanks, and copper genuinely does conduct heat better than aluminium on paper. But copper is heavier, more expensive, and its soldered joints are more prone to failing under vibration over time — which is exactly why virtually every radiator fitted to a car since the 1980s uses an aluminium core with plastic end tanks instead. Aluminium is lighter, allows thinner-walled tubes with more rows in the same physical space, and modern designs more than compensate for aluminium's lower raw conductivity through better overall surface area. The trade-off is repairability: a copper-brass radiator can often be resoldered by a competent specialist, while a modern aluminium-and-plastic radiator generally can't be meaningfully repaired at all — once the plastic tank cracks or the core develops a leak, replacement is the only realistic option, which is worth knowing before you spend money chasing a "fix" that a specialist might reasonably talk you out of.

The Three Failure Modes Worth Recognising Early

Radiators tend to fail in one of three ways. Leaks show up as cracks or corrosion in the core, in the tanks, or at the tank-to-core seal — the seal itself is a genuinely common failure point on plastic-tanked radiators as the plastic ages and shrinks slightly relative to the metal core it's bonded to. Clogging builds up gradually from dirt, sediment, and old degraded coolant, and gets significantly worse if different coolant types have ever been mixed, since some combinations react and gel inside the system. Overheating itself can also directly damage a radiator, since sustained excess heat degrades the rubber hose connections and plastic components faster than normal operation ever would — meaning a radiator that's overheated once, even briefly, is worth inspecting even if it seems to be working fine afterward.

Practical warning signs worth acting on immediately: visible coolant underneath the car (often sweet-smelling and coloured — pink, green, blue or orange depending on the coolant type), a rising temperature gauge, steam from under the bonnet, or coolant that looks rusty or has an oily sheen when you check the header tank. Low coolant without any visible external leak is also worth taking seriously — it often means the coolant is leaking internally into the engine oil or combustion chamber, which is a considerably more expensive problem than the radiator alone.

Coolant Type Matters More Than People Assume

Never top up with plain tap water on anything but a genuine emergency basis — the minerals in ordinary tap water accelerate internal corrosion over time. Manufacturers specify particular coolant formulations (commonly organic acid technology or hybrid formulations, colour-coded but not reliably so between brands) for good reason, since mixing incompatible types can cause the coolant to gel and block the very passages it's meant to flow through. If you're unsure what's already in your system, a full flush before refilling with the correct specification is the safer choice rather than guessing and topping up.

OEM vs Aftermarket: What Actually Changes

A genuine OEM radiator is built to your car's exact original specification and is the safest choice if you want guaranteed fitment and performance with zero guesswork, but aftermarket aluminium radiators — widely available for most mainstream makes — are frequently built to an equivalent or higher standard, sometimes with additional fin rows for improved cooling capacity over the standard part. Reputable aftermarket radiators from established suppliers are a perfectly sound choice for a like-for-like replacement; where OEM genuinely earns its price premium is in unusual trims, performance variants, or cars where a slightly-wrong core size affects clearance with other components in a tightly packaged engine bay. With reasonable care — regular coolant changes and prompt attention to small leaks — a radiator has a genuinely long expected lifespan, often 8 to 10 years, so a failure well before that point is usually a sign of a specific triggering issue (a stone impact, a coolant mixing mistake, or a period of overheating) rather than simple old age.