Do car radiator leaks just happen? According to the National Automotive Radiator Repair Association (NARRA), they do. NARRA studies suggest that leaks have more to do with age than mileage. This is the reason changing your vehicle’s coolant annually is such a good idea.
Although many external factors can cause a leak, such as impact, road salts, and chemical reactions, the most common breakdown happens inside the core itself. When your car’s anti-freeze gets old or overly diluted with water it cannot do its job lubricating and inhibiting corrosion. This problem is easy to recognize when the coolant fluid becomes discolored.
There are multiple warning signs indicating that your vehicle has a leak. The two most obvious signs are puddles of coolant under your car or truck, or an ongoing low fluid level condition. You’ll recognize the puddle under your car as radiator fluid by the bright, neon green color. Another sign that might not be as obvious is an unusual odor inside the car. It will be an annoyingly sweet smell.
Once you realize that your vehicle has a leak, the next step is to determine the location. The most common failure points are the radiator tanks, cooling and heating system hoses, petcock (drain valve), and the thermostat. If the smell inside your vehicle is exceptionally strong it is also possible that you have a heater core issue.
The best way to find a drip in the cooling system is to start your car, lift your hood and inspect with a flashlight. Be careful to stay clear of moving parts. Check the bottom hoses first, as this is very common.
If the issue is a hose you’re in luck. This is a very easy repair. Your local auto parts store will typically have the hose and new clamps for less than $25. You’ll also need a gallon of anti-freeze to refill the system after you replace the hose.
If the leak is in your radiator, you might be able to apply a “cold weld” temporary fix using an epoxy cement. The most popular product on the market for this is J-B WELD. It’s a two part epoxy that’s been around for decades. It offers a safe and reliable repair in engine compartments up to 500° F. It’s super strong and impervious to water, petroleum chemicals and acids. WARNING: It does not work on plastic (such as the plastic coolant tanks that are now common on most cars), but it works great on aluminum core or copper core cooling fins. Best of all, it only takes 2-3 hours to fully cure.