All too often the radiator of a vehicle is one of the first things to go on an engine. Luckily, there are a few emergency radiator repairs that you can do to help ensure you get to the nearest mechanic for permanent car radiator leak repairs. Just remember that these are only temporary repairs, and not permanent ones. These methods will work, though some will require some additional repairs if utilized.
Your radiator is an essential component of your coolant system. Without a properly functioning radiator, your engine can overheat and become inoperable. Learn to spot the signs of a radiator leak and how to seal a leak. This is our step-by-step guide on how to fix a radiator leak at home or on the road.
Signs Of a Car Radiator Leak
First, it is important to check for signs of a leaking car radiator. A small leak may be difficult to notice at first, but a major leak should be easy to identify. Here are the common signs of a radiator leak to watch out for:
- Rising temperature gauge
- Puddles of green or orange coolant under your vehicle
- Low coolant reservoir
- Discoloration or rust in your engine bay
A rising temperature gauge is one of the easiest signs to spot. A slightly higher temperature may be caused by other issues or by a minor leak, but if your engine temperature climbs too high you should avoid driving your vehicle. Driving while your temperature gauge is too high could damage your engine and create additional costly repair issues.
Inspect any puddles under your vehicle. One of the most common sources of liquid dripping from your vehicle is your air conditioner. Condensation naturally forms as your AC is operating, so this is not a cause for concern. Any yellowish or black colored liquid could be motor oil, and an orange or green color typically indicates a coolant leak.
How To Use Radiator “Stop Leak”
1. Prepare Your Work Area
Before you learn how to use radiator stop leak, you need to find the source of the leak. There are many areas of your radiator that could be cracked, so finding the leak can take some time.
Park your vehicle and wait for the engine to completely cool. Open the hood and wait up to a few hours before the engine is fully cooled. Radiators are pressurized systems, so be extremely cautious before opening your system or working in your engine compartment.
Use safety gear to ensure a safe maintenance routine. Safety glasses and gloves are recommended for safe inspection and repair. To spot a leak, it is best to first clean your radiator and surrounding components. Use a hose to clear off your radiator. Avoid wiping any part of the radiator as this could cause further damage to the fragile cooling fins of the radiator.
Once your car radiator is clean, check for any signs of cracks or leaks. A visual check of much of the radiator may be difficult as it is located typically behind your air conditioning condenser and partly covered by a fan shroud. As best you can, inspect the radiator, the end tanks, reservoir, and any surrounding tubing. If you don’t immediately see any leaks, turn on your engine and inspect your engine compartment.
2. Finding the Source of a Car Radiator Leak
A leaking radiator may be hissing, dripping, or spraying coolant. You may have to inspect your radiator on all sides to find the source of the leak. Be cautious when looking under your vehicle, as your radiator leak may be spraying hot radiator fluid.
For a professional test, purchase a coolant system pressure tester. These convenient testers are secured on either the radiator or pressure cap spout and create a seal. Be sure to follow the instructions accompanying the tester, ensuring the system is without pressure before removing the radiator cap. Once sealed, it pumps 10 pounds of pressure into the system. Check if your radiator can sustain 10 pounds of pressure. If the pressure drops, look for the source of the air leak.
Do not use more than 10 or 15 pounds of pressure, otherwise you could damage your radiator and cause even more leaks. Your coolant system is typically only rated for 15 pounds, so any more pressure could have adverse effects.
3. Seal Your Car Radiator Leak
There are a few common ways to fix your car radiator. Depending on the situation you are in, you can use either emergency fixes or commercial products. Using a commercial product offers a more reliable seal and avoids any additional damage to your vehicle, but there are a few household items you can use to fix your radiator temporarily in case of an emergency.
First, an easy solution for most leaks is commercial leak sealant. While this sealant is not as effective as the professional repair solution, it provides you with a reliable seal as you make your way to your local auto parts store or mechanic:
- Once your engine is cool, pour your sealant directly into your cooling system.
- Top off your radiator with coolant and water and seal your system.
- Run your engine for approximately 10 minutes and then let it sit overnight.
- Turn your engine on again to see if it has properly sealed.
Another solution is to use radiator epoxy. Once you have found a visible crack, clean the area thoroughly with brake cleaner exercising caution not to damage anything in the surrounding area. Once the area is completely dry, work your epoxy into a malleable putty and create a coat at least an eighth of an inch thick. Let it sit overnight and turn your engine on to test the seal.
Emergency Car Radiator Repairs
Quite often a radiator starts to leak at the most inopportune moment. Over the many years of driving old cars, I have had a few experiences of car radiator leaks on roads without a service station within an easy walking distance so these following are some methods to seal the radiator when the over-the-counter stop leak products are not available.
- Gum. Gum is a great item that can be used for emergency car radiator repairs. To get the most out of your gum repair you will need to do two things. The first is to identify where the leak in the radiator is, while the second is to chew the gum thoroughly. With the softened gum, simply place it over the hole, refill the radiator, and drive to your favorite mechanic shop.
- Bread. Bread can be used in much the same manner as gum. All you need to do is press a piece of bread against the leak in the radiator and hold it there for a little bit. The flour in the bread will dissolve just enough from the fluid in the radiator enough to work its way into the hole, and the heat will then cook the bread so that it won’t wash away.
- Eggs. For moderately sized holes you can use some eggs to plug the hole. Break the shell and put the raw egg into the radiator. The pressure will end up pushing the egg towards the hole, and the heat will cook it enough so that will plug the hole. While this method is effective (at least for a very short time) it will require that your radiator is flushed after the hole is fixed.
- Black pepper. If you drop a small amount of black pepper, such as the packets that you get from a fast-food restaurant, you can plug up small holes in your radiator. The pepper doesn’t dissolve and is forced towards the hole by the fluid escaping through the leak. This is another method that will require your radiator to be flushed after the repairs are made.
- Radiator sealant. There is a product available at most automotive parts stores that you can use which can end up working just as well, if not better, as most of the other methods listed here. All you really need to do is read the directions that come with the product and use it accordingly. Keep in mind that the sealant will usually only work on smaller holes about the size of a pin hole.
Finally
All these methods will get your classic car down the road after experiencing a car radiator leak, and hopefully home again or to your local repair shop. However, these are only temporary repairs to a radiator that will need more attention either from permanent repairs or core replacement from a radiator shop or purchasing a replacement radiator properly sized for your car and engine. Remember your cooling system is an integral part of keeping your engine running properly for years to come.
