If your vehicle's cooling system is having problems, it's most likely the radiator. This section is designed to spread the heat absorbed by the coolant as it flows through the engine, but a lack of coolant due to leaks or poor quality can degrade radiator performance. If your radiator is having problems, there are a few things you can try before taking your vehicle to a repair shop. However, keep in mind that an overheated engine can cause significant damage to internal components so it is best to seek professional services if the vehicle continues to experience temperature problems.
Step
Part 1 of 3: Identifying Problems in the Radiator
Step 1. Look for puddles under the vehicle
A definite symptom of a problem with the vehicle's cooling system is a pool of coolant under the vehicle. Remember, there is some fluid in your vehicle that could potentially leak, so check carefully to make sure it's coolant, oil, or simply water from the vehicle's air conditioner.
- Poke the puddle with your finger, then wipe it on a piece of white paper to make sure it's the original color.
- If it's green or orange, it's possible that the coolant is leaking.
Step 2. Check the coolant reservoir
If you believe the vehicle coolant is leaking. Most coolant reservoirs have a “boundary” label on the container indicating the level of coolant inside. Check the coolant level of the vehicle and refill if it is low. Check back after a few days to see if the altitude has changed.
- Make sure the vehicle temperature is the same every time you check the coolant level of the vehicle (eg always when it is cold before starting the engine, or when it is hot after driving).
- The appearance of a puddle accompanied by a decrease in the coolant level indicates a leak is very likely to occur.
- Refer to the vehicle's user manual to locate the coolant reservoir if you have trouble finding it.
Step 3. Watch the temperature meter change
If the engine lacks coolant, or the fluid needs to be replaced, the vehicle will have a hard time maintaining its ideal temperature. Monitor your vehicle's temperature meter. If the temperature seems to be consistently warming, or it starts to heat up sporadically, it's likely a problem with the vehicle's cooling system.
- If the engine fails to maintain its ideal temperature, it means that the coolant is low.
- The coolant will deteriorate over time. If the coolant level is still adequate but the engine is overheating, one of the reasons is that the coolant needs to be replaced.
- If you don't know what the symbols on the temperature meter mean, read the user manual to be sure.
Step 4. Look at the machine carefully
If you think the cooling system is leaking, flush the engine with a hose to rule out any signs of a leak. Then, start the engine and inspect the engine carefully for signs of a leak. Coolants are usually pressurized so the point of leakage is usually spray, bubbles, or even just a trickle of water. Wear protective eyewear and be careful when observing a running engine.
- Do not touch the machine while it is running.
- Look for new signs of a coolant leak and then drill down to its highest point for cracks or holes.
Part 2 of 3: Draining and Rinsing the Radiator
Step 1. Wait until the engine cools down completely
The cooling system is under pressure when heated so hot liquid can gush when the radiator cap or petcock valve is opened while the system is under pressure and cause serious burns. Leave the engine for a few hours to make sure it cools completely before touching the vehicle's cooling system.
- After a few hours, lightly tap the top of the radiator to see if it's cool enough to touch. If it's still warm, the cooler inside is still pretty hot.
- When opened while still hot, the cooling system will spit out very dangerous hot coolant.
Step 2. Jack up the vehicle
To access the bottom of the radiator to drain the used coolant, it's a good idea to raise the vehicle high enough that you can work and place the used coolant reservoir underneath. Locate the vehicle's jack point by reading the car's user manual to prevent damage during jacking up.
- Once the vehicle is high enough to slide the container underneath, install a jack stand to support the weight of the vehicle.
- Never work under a vehicle that is only supported by a jack. The jack stand will prevent the jack from losing pressure and lowering the vehicle while you are under it.
Step 3. Open the petcock valve and drain the coolant into the container
Locate the petcock valve at the base of the radiator. The petcock valve often looks like a spout that can be turned to open, and should be at or near the bottom of the radiator to drain the radiator. Once found, make sure the container is positioned under it and open the valve.
- The coolant should be cold when it exits the radiator, but you should still not touch it with your skin.
- Check the vehicle's user manual to determine the coolant capacity of the vehicle and make sure the container is large enough to hold everything at least twice.
Step 4. Rinse the radiator using a hose
After the radiator has finished draining, there is still a fair amount of bad coolant in the system. Close the petcock valve and fill the cooling reservoir with water. Start the engine and let it sit for a few minutes before draining the radiator again. We recommend repeating this process 2-3 times.
- If the car is only allowed to start for a few minutes at a time, it's best not to get it too warm to allow the radiator to drain.
- The water will flow with the used coolant from the engine.
Step 5. Refill the radiator with a mixture of water and coolant
Most vehicles require a balanced (50/50) ratio of water and coolant mixture to maximize cooling system efficiency. You can buy pre-made coolant, or make your own. Fill the reservoir to a few centimeters above the “full” line, then start the engine. When it warms up, the thermostat opens so that coolant can enter. When the coolant level drops in the reservoir, continue adding it. Pour the mixture into the radiator or reservoir until it reaches the maximum recommended capacity.
- If you do not have a user manual, check the manufacturer's website for your vehicle's fluid capacity.
- It may take a few minutes before the coolant drains into the system so be patient when pouring new coolant.
- If your vehicle's radiator has a bleeder valve at the top, open it and let the engine run for 10 minutes to allow any remaining air to escape.
Part 3 of 3: Sealing Leaks in Radiator
Step 1. Replace the radiator cover
A common point of damage to radiators is in the cap itself. The radiator cap is designed to let excess air out to prevent damage to the cooling system, but over time it can oxidize, become filled with grease, or simply wear out. To replace the radiator cap, simply wait for the engine to cool completely and twist the old cap off. Put the new cap in place.
- You can buy a new radiator cap at the nearest repair shop.
- Be sure to ask for a cap that fits the year, make, and model of the vehicle.
Step 2. Use a commercial sealant
Commercial leak sealants are sold in repair shops and can help fix radiators in an emergency. However, be aware that this product is not a permanent solution. The sealant is applied by removing the radiator cap when the engine is cold and pouring it out. Refill the radiator with a mixture of water and coolant if there is only a small amount due to a leak.
- You will still need to find and fix the leak, or replace the radiator after applying the sealant.
- This sealant is great if the car needs to be taken from home to the repair shop.
Step 3. Seal any visible cracks with epoxy
If you can find the location of the crack in the radiator, you can repair it with epoxy. First, clean the area around the crack thoroughly as dirt and oil can prevent the epoxy from sealing properly. Use brake cleaning spray to get rid of the oil build-up, then allow the cleaned area to dry completely. Massage the epoxy by hand until it is soft enough to spread throughout the crack.
- Allow the epoxy to harden overnight before starting the vehicle.
- Radiator epoxy can be purchased at most repair shops.
Step 4. Replace the radiator
If there is a crack in the radiator, you will most likely need to buy a replacement. To replace the radiator, drain all the fluid from it and disconnect the hoses entering and leaving the radiator. Open the bracket frame that holds the radiator and slide it up and out of the front of the vehicle. Different vehicles have various mounts but usually the radiator is mounted with 4-6 screws. Slide the new radiator back into place and screw in the screws as before.
- You can remove the body or cut the panel to access the radiator bolts or remove the radiator from the vehicle.
- You can buy a new radiator from the vehicle manufacturer or most repair shops.
