A Guide to Car Radiator Repair

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Radiator repair is an essential part of both maintaining your car and extending its working life. When your radiator is working, it keeps the temperature of your engine under control. When it’s not, your engine risks overheating, creating the potential for permanent damage that can total your car.

Here’s a look at how to find and fix problems with your radiator so you can keep your car for years to come.

Car Radiator.
Car Radiator.

What is a Car Radiator?

Before we get into the problems and solutions portion of this write-up, let’s define what a car radiator is.

The radiator is a part of a car’s cooling system.

Think of it as a heat exchanger made up of two water tanks. The radiator removes the heat from the coolant that runs through your engine and moves that heat to the outside of your car.

How Does a Radiator Work?

The engine pumps hot coolant into your engine. That hot coolant flows into one of the tanks in the radiator before being pumped into the core of the key cooling part of your engine.

The narrow tubes that comprise most of your radiator bring cold air into your car as your vehicle travels forward. This cold air pulls the heat from the coolant. The newly cooled fluid is then pumped back into your engine from the other end of the radiator.

This coolant can now do its purpose of keeping the temperature of your car under control. Many newer radiators also include a fan controlled by a thermostat that pushes hot air through the radiator when the car is stationary.

What are Problems with Car Radiators?

The very function of the radiator opens it up to many problems.

The most common problem with radiators is leaking.

The hoses that connect your radiator to your car will fail at some point. Also, the clamps that connect these pipes will loosen as well. If you see a green fluid dripping from or on your engine that smells sweet, you’ve got a leak.

If you see a green fluid dripping from or on your engine that smells sweet, you’ve got a leak.
If you see a green fluid dripping from or on your engine that smells sweet, you’ve got a leak.

The frequent amount of liquid that flows through the radiator’s pipe makes it prone to rusting (another cause of leaking). So, be sure to check the exterior of the pipes for signs of rust. Also, you need to look for a brownish color in your coolant.

One of the more frustrating problems to deal with is mineral deposits, or gunk, building up inside your radiator. Rusty pipes and leaks are easy to detect. But gunk is much harder to find and can cause the same issues the previously mentioned issues can create.


Leaky fluid, rusty pipes, and gunk can all lead to overheating. And I don’t think we have to go into too much detail why overheating is a problem for your car.

Cracked Radiators

Other parts not directly connected to the radiator can cause problems for it as well. A broken water pump or faulty thermostat can lead to too much fluid flowing into the radiator. And too much fluid will crack the essential part of your cooling system.

Cracked radiators show the same signs as the previously mentioned issues: leaking fluid, higher engine temperatures, and the low coolant light coming on.

How to Fix a Car Radiator?

The best repair for a leaky or cracked radiator is to replace it. But there are other solutions for how to repair a radiator that are useful if you are not able to afford a brand-new radiator right now.

First, you need to make sure the leak is actually coming from the radiator. If you can’t see the leak, use a pressure tester. Pump the tester to 15 PSI and the leak will reveal itself.

Once you can confirm that the origin is the radiator and have found the leak, use one of several potential temporary solutions. These include industrial solutions such as using cooling system sealer as well as more unconventional remedies such as using an egg, epoxy glue, or black pepper.

The epoxy glue is also good for sealing cracks in your radiator.

How To Pressure Test Your Radiator

What about gunk and mineral deposits?

Clean out the pipes of your radiator to take care of these hard to detect issues. Many times, flushing the coolant in your car is all you need to do to take care of the problem.

Now, you need to follow these steps:

  • First, give your car a couple of hours (at least) to cool down. Coolant is hot right after use, and it is a danger to handle right after you drive.
  • Second, get a container and jack your car up.
  • Then, locate the petcock and open it so the fluid can drain into your bucket.
  • Once you’ve emptied the petcock, flush the radiator with a hose (close the petcock before you do this). You should also fill the coolant reservoir with water before doing this. Start your car so the remaining coolant will run through your engine.
  • The last step is putting a new 50/50 mix of coolant and water into your system.

How Much Will a Radiator Repair Cost?

Now, many of us would not be comfortable with performing the previously mentioned auto radiator repairs on our cars. And those steps may not be enough to get the problems with your radiator taken care of.

So many car radiator repairs are best left to professionals.

Now, professionals will most likely replace the part entirely. And replacement cost an average of about $600 (though that can vary anywhere between $300 to $1500 depending on the car).

Repair procedures will obviously cost a lot less. Flushing coolant cost about $50 if you do it yourself, while a mechanic will charge about $90.

Can I Drive My Car with a Cracked Radiator?


Well, that was easy.

I mean, sure, you might be able to drive around with your radiator cracked for a while. But when you do, you take on great risk of your car overheating, possibly catching fire.

So, address a cracked radiator immediately!!!!


Radiator repair is a necessary part of keeping your car running. Do not hesitate when you sense a problem with your car radiator. Get the issue taken care of as soon as possible.

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