How to Properly Install or Replace a Radiator

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How to Properly Install or Replace a Radiator

A radiator is not a common replacement part, but vehicle owners are required occasionally to replace this key part of the engine's cooling system. Radiators can fail due to damage to the cooling rods that run through the fins, leaks that develop at weld points, or from rust forming in the cooling system that eats away at the radiator internally. Scale or rust deposits can also form and clog radiator passages, causing the engine to overheat.

Fortunately, installing a new radiator in a car or truck is not an extremely difficult job; people with some basic technical skills and the ability to operate hand tools can perform a radiator replacement by following simple instructions. Radiators are available at auto parts stores, dealership parts departments, and radiator remanufacturing shops. Additionally, sellers on eBay offer a good selection of new, used, and remanufactured radiators at competitive prices.

Testing a Radiator for Leaks or Blockages

Vehicle cooling systems operate at high temperatures under significant pressure, so safety is a primary concern when working with radiators at their normal operating temperatures. Always wear safety glasses and leather gloves for protection from hot fluids. Never take off a radiator cap without releasing pressure or waiting for the radiator to cool. The following steps can help determine if there is a problem with a vehicle's radiator.

Performing a Radiator Pressure Test

Beginning with a cool radiator, remove the radiator cap, and top off the coolant level in both the radiator and overflow tank to the proper level. Read the pressure rating on the radiator cap to know what pressure to test the system at. Using a pressure tester designed to fit on the mouth of a radiator, tighten the test cap to seal the radiator. Pump the pressure tester up to no more than 120 percent of the pressure reading on the radiator cap, and inspect the radiator for leaks. If there are no leaks, leave the pressure on the system for five to 10 minutes to see if the pressure drops, indicating the potential for an internal leak in the engine.

Pressure Test the Radiator Cap

Using an adapter, place the radiator cap on one side of the adapter and the pressure cap on the other side of the adapter. Pump pressure into the adapter until it reaches the pressure rating on the radiator cap. See if the cap is able to hold the pressure for five minutes, or if the pressure slowly bleeds off, indicating a failure of the radiator cap itself. A cap that does not hold sufficient pressure can cause the cooling system to overheat and lose coolant.

Testing a Radiator for Blockages

If the vehicle has a radiator cap located on either side of the radiator assembly, then it is possible to see down one side of the radiator rods or tubes. With the radiator cap off a cool radiator, visually inspect the interior of the radiator with a flashlight to see if the rod ends are crusted over with scale deposits that can prevent the coolant from flowing properly.

Using an Infrared Thermometer to Test for Radiator Blockages

An infrared thermometer is an accurate temperature-measuring device. With the radiator at normal operating temperature, shut the engine off to allow close access to the radiator. Point the infrared thermometer at different places on the radiator, and the reading should be consistent. A spot on the radiator that reads several degrees cooler is an indication of blockage.

Tools and Supplies Needed to Replace a Radiator

Having the necessary tools and supplies readily available to remove and then install a new radiator can speed up the process and make the task easier. Other than line wrenches, the tools required are basic hand tools that are commonly found in tool chests. The following chart provides a quick reference for these tools and supplies and their use.

Tool or Supply



Removing and installing hose clamps

Wrenches, or sockets, and a ratchet

Removing and installing attachment hardware

Line Wrenches

Loosening and tightening automatic transmission cooler lines

Hose clamps

Install new hose clamps


Install new coolant


Be sure to install the same type of engine coolant that was drained from the radiator. Also, the red coolant of Dexcool should not be mixed with the more common ethylene glycol, which is normally yellow or green.

Removing the Radiator from a Vehicle

Before beginning the process of removing a radiator, it is important to wait until the temperature of the radiator has cooled to the point that it can be handled with bare hands. Locate the petcock or drain valve of the radiator, and place a drain pan under the vehicle below the drain. Remove the radiator cap, open the drain, and allow the coolant to run out. While the radiator is secured in place, loosen the clamps on the upper and lower radiator hoses, and pull the hoses loose.

Remove Automatic Transmission Cooler Lines

If the vehicle has an automatic transmission, use line wrenches to loosen the transmission cooler lines. A line wrench is similar to a box end wrench with an opening to allow a line attached to a fitting to slip into the centre of the wrench. The advantage of a line wrench is that it does not slip off the fitting like an open end wrench and cause the attachment points on the fitting to round off. Once the line is broken free with the line wrench, an open end wrench can be used to loosen and remove the attachment fitting.

Remove Attachment Hardware

Most vehicle radiators sit in a cradle formed by an upper and lower core support, which is a part of the front cross member of the vehicle. Rubber pads cushion the radiator on the bottom and top to provide vibration insulation and prevent the radiator from rubbing with the supports. The top core support may also include the bonnet slam panel where the bonnet is held down with the latch. There may also be support pieces that reinforce the core supports leading to a shock tower or part of the frame. Remove the top radiator support panel, and lift the radiator out.

Installing the New Radiator

To install the new radiator, one may simply reverse the process, but it is important to follow a few critical steps during the installation. Be certain to not damage the fins of the radiator while installing the radiator back into the vehicle. See that the new radiator seats into the rubber cushions that hold the radiator in place and keep it from vibrating or rubbing against other metal parts that could damage the radiator.

Start the fittings on the transmission cooler lines by hand to make sure they do not cross thread when tightening. Torque the cooler lines tight with a line wrench to prevent an open-end wrench from slipping and damaging the fittings. Use new hose clamps to install the radiator hoses. After filling the radiator, check the coolant level after the vehicle warms up and the thermostat opens; it may be necessary to add more coolant.

Buying Radiators, Tools, and Supplies on eBay

Using eBay as your one-stop shop for buying everything you need to replace a radiator is easy and convenient. Sellers on eBay offer new, remanufactured, and used radiators that fit a wide selection of vehicles. You can also find tools and supplies such as radiator clamps, radiator hoses, or radiator caps listed on eBay. Searching for radiator parts on eBay only requires you to enter the name of the item you are looking for, such as "radiator", as a keyword into any eBay search bar. To narrow the results displayed, use specific keywords, such as "Honda Prelude radiator", to match the listings to the vehicle you own. To find radiators or tools at promotional prices, be sure to look within the eBay Deals section of the website.

After selecting the item you wish to purchase, it is important to look into the seller's background. You can do this by checking the seller's feedback rating to see how previous buyers rated their transactions with the seller.


An owner who decides to replace a radiator in a vehicle can save a significant amount of money as compared to paying a professional technician to perform the job. By following a few safety rules and some tips to make the job easier, the task of removing the radiator and installing a new one is not that difficult to perform. Having the right tools on hand and all of the supplies necessary to complete the job is a key to performing the process efficiently. Vehicle owners who recognise a problem with the cooling system in a vehicle are wise to address the concern as quickly as possible. Delaying a repair to the coolant system can cause the engine to overheat and has the potential to seriously damage internal engine components.

Radiator|Used Radiator|Pressure Tester|Infrared Thermometer|Vehicle

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