How to Repair an Aluminum Radiator

February 16, 2012

If an aluminum radiator is damaged or is experiencing problems, it can easily be fixed up by the owner. Below is a guide on how to repair an aluminum radiator.

Cleaning The Radiator from Inside

First of all, the radiator has to be cleaned from the inside. The things that have to be cleaned from inside the damaged radiator include oil, grease and antifreeze. The radiator's inside can be cleaned with alcohol. The alcohol should be poured in the radiator after draining out the coolant. Then the radiator has to be turned so that the alcohol can reach the damaged area, hence cleaning it from the inside.

Cleaning The Radiator from Outside

After cleaning the inside, the damaged area has to be cleaned from the outside with alcohol and then a non-flammable break cleaner has to be sprayed over the area to remove any oils. This has to be done before applying the adhesives on the surface.


The radiator's side with the least damage has to be selected and it has to be taped over. The tape should cover a much larger area than the one that is actually damaged.

Dealing with The Damaged Fins and Tubes

The damaged fins have to be pulled away from the damaged tubes, with the help of a pair of needle nosed pliers. The tubes' ends have to be crimped if possible.                                               

Making The Patch

The radiator has to be put down with its taped side facing downwards. After that the ingredient of the patch should be prepared. The patch can be made using either the J-B Weld or the J-B Kwik.

Using The J-B Weld

The J-B Weld is the perfect aluminum welding solution. It is to be mixed with alcohol that acts as a thinner. This mixture than has to be poured into the damaged areas of the radiator. The welded area then has to be heated with the help of a hair dryer.

Using The J-B Kwik

The J-B Kwik is basically an adhesive that has to be applied on the damaged area and it will dry out in a period of just 15 to 20 minutes.

Drying The Patch

In case the repair work is being done in a cold climate, then the patch has to be dried with the help of a hair dryer. This is to be done till the time the patch settles down and hardens.

Plugging The Outlets - Method 1

The one way to plug the outlets is to use a testing radiator cap and then pressurize the radiator with a pressure of no more than 25 psi. 

Plugging The Outlets - Method 2

Another way to plug the outlets is with two radiator caps. A vacuum has to be created with a hand squeeze pump. If after 2 to 3 hours the vacuum still remains, it means that the aluminum radiator is repaired

Cleaning The Radiator

After checking the aluminum radiator thoroughly, it has to be cleaned for any extra adhesive or oil.

Putting It Back in Place

Once everything has been done properly, the aluminum radiator has to be put back in its place. 

Related Questions and Answers

Radiator Material: What are the Most Common Types?

The most common types of radiator material are aluminum and copper, although most modern radiators are made of aluminum. Aluminum is the preferred alloy because of its light weight and high heat dissipation. Some car radiators are made from a combination of metals. For example, a car radiator may have an aluminum core, with other alloys making up the rest of the radiator. Other radiator materials include brass and lead, but these metals are not used commonly. If brass and lead are used, it is generally in combination with aluminum.

What is the Difference Between Stock and Aftermarket Radiators?

There is no inherit difference between stock and aftermarket radiators. However, an aftermarket radiator may be better equipped to handle high-performance applications, depending on its alloy type and capacity. Aftermarket radiators tend to be less costly, as is the case with most aftermarket parts. Some believe aftermarket parts are of a lower quality than stock or OEM (original equipment manufacturer) parts, but this is not necessarily the case. Other than cost, one may choose to install an aftermarket radiator if the stock radiator is ill-equipped to deal with the application of the vehicle, such as in auto racing.

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