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How to Fix a Cracked Radiator Metal: Everything You Need to Know!

How to Fix a Cracked Radiator Metal

If you suddenly have issues with the cooling system of your vehicle, it could be caused by your radiator. The radiator is the central component of its cooling system. It is the one that helps get rid of the excess heat from the engine by cooling its fluid. A cracked radiator can cause this fluid to leak which will cause low coolant levels and when this happens, the radiator won’t be able to do its cooling task. Knowing how to fix a cracked radiator metal can help you fix this issue and help you save some money as well. Fixing a cracked radiator metal can be usually done by patching it with epoxy, using stop leaks, or by soldering the metal. If the crack is too severe, a radiator replacement will be needed. 

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Although there are a number of ways on how to fix a cracked radiator metal, that does not mean that you will just have to pick one and perform it. It might sound a good solution but not all of the methods are good and appropriate for your radiator. There are still some factors that you need to consider before you pick which repair method you choose. 


How to Fix a Cracked Radiator Metal: What are the signs of a cracked radiator? 


Before we learn how to fix a cracked radiator metal and the signs of having one, we need to understand how a radiator works. It is already known that the engine can cause an enormous amount of heat since it needs power through burning of fuel and creating energy from its moving parts. That is why during the operation of the engine, there should be something that helps vent the heat to keep the engine from overheating and it is the radiator. 


The radiator gets rid of this heat from the engine. It is a vital component of the cooling system that also consists of a liquid coolant, hoses, a fan, and a thermostat. The coolant moves  through the hoses from the radiator, then takes in the excess engine heat by moving through the engine, and travels through the radiator again.  


When the coolant is in the radiator again, its thin metal fins will release the coolant heat to the outside air while the hot fluid passes through it. With the help of the cool air that flows into the radiator through the grille of the vehicle and the system’s fan when it is idling, it  lowers the temperature of the coolant and eliminates the hot air out of the vehicle.  


Since the radiator plays a very important role in the vehicle’s cooling system, you can expect some issues to occur when it is cracked or damaged. What are the signs of a cracked car radiator? 


  • Leaking coolant. If you notice a pool of coolant under your vehicle while it’s parked, it is an indication that there is something wrong with it. It could be caused by a cracked radiator or a hose problem. Whatever caused the coolant leak, you need to have it checked by a mechanic immediately for a proper diagnosis.  


  • Overheating. When your radiator is cracked, it could cause the coolant to leak. When the coolant level goes way too low, the radiator won’t be able to do its task which is to get rid of the excess heat of the engine. This causes the engine to overheat. 
  • Low coolant level. Low coolant level or a flashing low coolant light that makes you constantly add coolant to the radiator could mean that you have a leaking one. It is best that you have it inspected so you can correct the problem. 


How to Fix a Cracked Radiator Metal: Can you repair a cracked radiator?


Like mentioned earlier, there are several ways on how to fix a cracked radiator metal but not all will be good to your radiator. Here are some of the factors that you need to consider. 


  • Before you know how to fix a cracked radiator metal, you need to identify what material your radiator is made of. It is usually made with a copper-brass core or an aluminum core. Its tanks usually have aluminum, brass, or plastic depending on the core material.  
  • Next is you need to identify the leak or the crack. If you notice your coolant leaking, you don’t automatically assume that it is caused by a cracked radiator. There are instances where the leak is caused by the radiator hoses, tank connections, radiator tubes, and the header plates. 
  • Aside from the location of the leak, you also need to know why the leak occurred. There are some damages that can’t be repaired by just fixing the crack or leak but will require a radiator replacement. You need to check for pinhole leaks. You might not be able to see the actual hole but you can see the coolant coming out. You also need to inspect for any severe  damages on the metal like large holes, tears, corrosion, or bulges. Separation of the tank from the core is considered a severe damage, too. Severe damages to the radiator will mean that you need to replace it.
  • Keep in mind that aluminum radiators can’t be repaired the same way as the copper-brass. An aluminum radiator will begin to suffer from metal fatigue as it is used. Repairs done to aluminum radiators don’t usually last since the metal expands and contracts, weakening it as it heats and cools. If you choose to weld the cracked area, the metal is still weak and will likely get damaged again.   
  • Copper-brass radiators are the ones that can be repaired effectively because of their solder construction. It enables this type of radiator to be dismantled, cleaned out, and be soldered again. However, it can only be done effectively when the damage or crack is not that severe. 

How to Fix a Cracked Radiator Metal: How can you repair a cracked radiator?


When you suspect that you have a cracked radiator and you are dealing with a leak, it is advised that you have it repaired immediately. You can have it repaired in a repair shop or if you know how to fix a cracked radiator metal, you can opt to do the fixing yourself. Here are some of the ways on how to fix a cracked radiator metal.


How to fix a cracked radiator metal using a radiator epoxy. 


Using a radiator epoxy to fix your aluminum radiator is a cost-effective way to correct the leaking problem. All you need to do is follow these simple steps.


  • You will need to locate the crack or damage first. To do this, you need to cool down your vehicle completely. You need to make sure that it is already turned off. 
  • Once you have located the crack, you will need to drain the radiator or until just below the cracked area. 
  • You can then proceed to clean the area using a brake cleaner. It is important to completely clean it and its surrounding area so the epoxy will bond really well. Sanding the area can also help make a better bonding action with the epoxy. 
  • Once the area is clean and dry, get the epoxy strips, break a piece off, press, and rub it together until you feel that it’s softer. It will become more pliable the more you work with it. 
  • Apply the epoxy generously and make sure that you cover the entire area. Remember to take your time when you do this process. You need to ensure that the layer has been applied correctly so the epoxy will still remain stable when the pressure builds up inside the radiator. Wait until the epoxy fully cures and becomes hard. It is best that you leave it to fully harden overnight before you use your vehicle again. 
  • Before you start your vehicle, you need to check everything. Check if you have reinstalled anything that you removed and there is a good amount fluid in the radiator. Check the patch of epoxy you applied and see if it is secure. 
  • Start your car and see if the spot is still leaking. Run the engine for a while to build up some pressure. Check the patched area again if the epoxy is still there. If it is not leaking anymore after a while, it means that you have fixed it properly. 


How to fix a cracked radiator metal by soldering.

Soldering can be done to repair a copper-brass radiator if it has a hole or a leak that is not that big or wide. 

  • Assuming that your car has already been cooled down and the location of the leak has already been found, you will need to clean the surrounding area with a brake cleaner. You also need to remove any obstructions or paint from the cracked area. You can use a small grinder or steel wire brush to make sure it’s clean. Just be careful and not use enough force while cleaning so you won’t cause any additional damage or make the crack bigger.  
  • Pro tip. When you solder a radiator, you need to make sure that you will be using a high wattage soldering iron and a thick soldering wire or a heavy gauge. When you use a low-wattage soldering iron, chances are, it will not properly melt the soldering wire and the radiator together because it will not produce the needed heat.  It is recommended that you use a heavy duty soldering iron like those that are 60 watts or more. 
  • Once the area is clean and dry, you can now proceed to solder the radiator. To do it properly, you need to heat the damaged area of the radiator first by holding the soldering iron’s tip to the radiator until it is hot enough to take the solder and the wire. Once the cracked area of the radiator has been heated enough, solder the wire into the radiator slowly. Make sure that the cracked area or the damage has been covered completely with a sufficient amount of solder. Doing so can keep the cracked area of the radiator from leaking again. 
  • Once the soldering is done, you will have to grind that area to make it a bit smooth using a wheel grinder or a steel brush. Make sure that you only grind just enough to remove the burrs or sharp edges of the soldered area. Grinding it down to level the soldered area with the rest of the radiator is not needed.


Additional Tip:

  • You might have heard that one of the ways on how to fix a cracked radiator metal is by adding pepper or perhaps an egg yolk to the radiator. They said that this can stop pinhole leaks. It is best that you do not do this. You don’t want your coolant to have any foreign substance that can flow through your engine. It is best that you fix your cracked radiator the proper way. 
  • Fixing an aluminum radiator by patch welding is also not being recommended. The aluminum metal of the radiator is already fatigued and will need a replacement.  Welding it to repair a crack might not just be enough. Even if you think that the patch is holding the damage securely, sooner or later, other areas will also start to fail.


Learning how to fix a cracked radiator metal will be useful especially if you want to save money. Instead of having to pay the repair shops or the mechanics, you will just have to buy the needed parts and do the fixing yourself. But as much as it is useful and important, knowing how to follow proper car care to prevent problems such as a cracked radiator metal from happening will be more beneficial. 

To avoid this problem, unnecessary expenses, and a lot of repairs, you need to change your vehicle’s coolant at the recommended intervals. You also need to clean your copper-brass radiator regularly to make sure that it will last a long time. Prevention indeed, is better than cure!



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