Alloy Radiator Buying Guide

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Alloy Radiator Buying Guide

The main function of a car's radiator is to keep the engine at a safe and efficient temperature. To do this, coolant is pumped through the engine's cooling passages, absorbing heat while it travels. Then, the coolant leaves the engine through the radiator hose and enters the radiator. It runs through a number of finned tubes in order to increase the surface area to allow the heat to dissipate. Coolant at a lower temperature is pumped back into the engine and the cycle is repeated.

Replacing a traditional radiator or upgrading to an alloy radiator may seem tricky, but understanding its construction, alloy metals, and the factors to consider when buying, simplifies the process. Alloy radiators are available from vehicle part suppliers, auto stores, and online from eBay.

When to Replace a Radiator

A car or truck radiator may need to be replaced due to deterioration or as part of an engine upgrade. Knowing when to replace the radiator is essential; a faulty radiator can destroy an engine. If there are pools of coolant under the car after it has been parked for a while, obvious water leaks, or constant coolant loss, it is time to replace the radiator. Have the car or truck's make, model, and year to hand when searching for a new radiator and use this information as a guide.

If the engine has been upgraded and produces more power, it generates more heat and a radiator upgrade is required. In this instance, get expert advice from a specialist. The alloy radiator upgrade must be able to handle the new heat load, fit in the available space, and it may be necessary to adapt the mountings for installation. Searching for alloy radiators by using only the make and model of a car or truck with a new engine will not be adequate, although this should be taken into account as it determines the space available and the mounting method.

Types of Radiator

There are two main types of radiator used in modern car and truck engines: cross flow and down flow. Both have upper tubes where heated radiator fluid enters the system and bottom tubes where cooled liquid exits. The primary difference between the two is the location of the coolant tank. In a cross flow radiator, the coolant tanks sit on the sides of the radiator core and the coolant cycles back and forth across the core. These tend to be cheaper than down flow radiators and allow for lower bonnet heights. In a down flow radiator, the coolant tanks sit above and below the radiator core. This vertical-flow design is popular in heavy vehicles.

Construction of an Alloy Radiator

An alloy is a mixture of metals, usually melted together, that forms a new metal with characteristics that are different to those of the individual metals in the mix. Aluminium alloy is a mixture of primarily pure aluminium and other alloying elements. Adding these elements creates particular characteristics, such as strength, conductivity, ductility, or machinability.

Types of Alloy for Radiators

Aluminium alloy radiators are able to produce 30 percent more cooling, can withstand higher coolant pressures, are stronger than brass or copper radiators, and tend to be 40 percent lighter than traditional models. In addition, they are corrosion resistant and tougher than their plastic counterparts. However, copper-brass alloys offer superior cooling properties, making this alloy the preferred choice for high performance vehicles or stationary applications. These are usually more expensive than aluminium alloy models.

Features of Alloys for Radiators

The construction of an alloy radiator determines its durability and efficiency. Choose an alloy, such as aluminium alloy, that is strong, dissipates heat well, and is corrosion resistant. The way the components have been fitted together also determines durability. Where possible, choose alloy radiators with tungsten inert gas (TIG) welded joints rather than those joined with epoxy glues. Epoxy acts as an insulator, reducing the efficiency of the radiator. In addition, consider the fin density, measured in fins per square inch (FPI). The higher the number of fins, the faster the heat dissipation. 12 FPI is standard.

Alloy Radiator Tubing

Since the cooling action of the radiator relies on the coolant running through the tubes, the quality and construction of the tubes are important. Wider tubes maximise the surface area, causing heat to dissipate faster as more of the liquid is in contact with the tubes. However, it is important to strike a balance between heat dissipation and efficiency, so the tubes should not be too thick. If in doubt, seek expert advice.

Components of an Alloy Radiator

Before buying an alloy radiator, learn how the components work together to dissipate heat. The table below lists and describes the main parts of a car or truck radiator.

Radiator Component



Multiple tubes passing through

Absorbs and dissipates heat from the coolant running through the tubes


Boosts the flow of liquid through the tubes

Ensures all liquid comes into contact with the fins by creating turbulence

Turbulence mixes warm and cool liquid to ensure even heat dissipation

Radiator cap

Keeps air out of the coolant

Acts as a pressure valve

Coolant is warmed slightly and excess pressure is released through the cap

Radiator core

Warm coolant passes across the core to lower the temperature

More cores means a greater cooling surface, but a thicker radiator

Practicality of additional cores depends on cooling requirements and the space available

Aluminium alloys used for lower cost and weight

Brass-copper alloys suitable for high performance

Copper alloys gaining popularity due to superior performance

Copper alloy heat exchanger CuproBraze used in radiators for modern diesel cars and trucks

Radiator fans

Electrical or mechanical

Electrical fans are preferred for use in modern vehicles

Mechanical models driven by a fan belt

Mechanical fans use as much as 20 horsepower

The way the coolant moves through the engine and the car radiator affects the safety and efficiency of cooling. Different metals and materials react to heat in different ways. Some retain heat, while others allow it to dissipate. Aluminium is a good conductor that does not retain heat, making aluminium alloys a firm favourite when it comes to radiator production.

How to Buy an Alloy Radiator on eBay

eBay sellers offer a wide selection of alloy radiators for a variety of vehicles. Browse the selection available or search for a specific kind by typing a phrase, for example "Holden Commodore alloy radiator", into the search field, which is available on every page. Refine your results by choosing the most appropriate category and item specifications. Check the eBay Deals for items at a lower price or with free delivery.

Before buying on eBay, take the time to learn all you can about the item and the seller. Read the full item description and check the images included. When buying bulky or heavy items, look for local sellers that allow pickup to save on postage costs. Always check the seller's feedback information.


Alloy radiators for cars and trucks tend to perform better when compared to traditional or plastic models. Aluminium alloy remains a popular choice, but copper-brass alloys are preferred for their high performance. When replacing a radiator, use the vehicle's make and model to search for a new product. When upgrading a radiator, get expert advice to ensure that the radiator performs as required and fits the vehicle.

With alloy radiators, choose TIG welded construction where possible. Epoxy glue acts as an insulator and reduces efficiency. Welding also tends to be more durable. The more fins, the faster the heat dissipation. In addition, wider tubing means that more coolant comes into contact with the surface of the tube and heat dissipates faster. Alloy radiators are available on eBay for a range vehicles.

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