Follow the following steps to clean.
Step 1-Start
First, make sure the engine is cold. A hot engine means the radiator is filled with hot coolant under extremely high pressure - and you can get burned when you open the radiator cap. Cold water can also damage hot engines.
Step 2 - Clean the water tank
Open and secure the hood securely to avoid accidental slipping. Then, use a nylon brush and soapy water to gently scrub away any dead bugs and debris that have collected on the tank grate. Be sure to scrub in the direction of the radiator fins and not in the opposite direction, as metal is fragile and can bend easily. Once the grate has been cleaned, direct a gentle stream of water from the hose above the grate to make sure all debris has been completely removed.
While flushing your radiator only happens every two years, it's a good idea to clean the radiator grille every 12,000 miles or so.
Step 3 - Place the drain pan
It is very important to properly drain the spent coolant. The coolant is highly toxic but has a sweet taste that attracts children and animals. Do not release unattended or on the ground. Make sure you don't use the drain pan for any kitchen purposes - a disposable drain pan is ideal. The drain pan should also be small enough to easily fit under your vehicle.
Once you have found the appropriate drain pan, slide it under your vehicle and center it over the radiator drain valve (also known as the drain plug)
Step 4 - Inspect the radiator Cap
The radiator cap serves as the lid of the radiator, sealing and pressurizing the coolant inside the radiator to keep the engine cool. Coolant pressure varies depending on the engine, and the pressure rating is marked on the top of the cap itself.
A water tank cover contains a spring coil stretched between a wide flat metal at the top and a smaller sealing rubber at the bottom. The tension between the spring and sealing rubber is key to allowing the lid to maintain pressure, so if you can easily compress the two, the tank lid is worn and should be replaced. Another sign of replacing the tank cap is any rust or dryness in the sealing rubber. Generally speaking, the tank cap should be replaced at least every two years, so when flushing the tank, you can make it part of your routine. Keep in mind that different radiator caps have different pressure ratings, so be sure to keep the ratings in your vehicle records.
Step 5- Check the clamps and hoses
The next step is to check the water tank rubber hoses and clamps. There are two hoses: one at the top of the tank, which discharges high-temperature coolant from the engine, and one at the bottom, which circulates cooled coolant to the engine. The water tank must be drained to facilitate hose replacement, so check them before you flush the engine. This way, if you notice signs of a crack or leak in the hose or the buckle clip looks rusty, you can replace them before refilling the tank. Marks of soft, porridge-like gunk mean you need a new hose, and if you find only one hose with any of these marks, still replace both hoses.
Step 6 - Drain the old coolant
The radiator drain valve (or drain plug) should have a handle that makes it easy to open. Simply unscrew the twist plug (wear work gloves - the coolant is toxic) and allow the coolant to flow into the drain pan you placed under your vehicle in step 4. After all the coolant has been drained, replace the twist plug and pour the old coolant into the sealable container you have nearby. Then place the drain pan back under the drain plug.
Step 7 - Flush the Tank
Now you are ready to perform the actual flush! Just take your garden hose, insert the nozzle into the tank filler port, and let it flow all the way. Full. Then open the twist plug and allow the water to drain into the drain pan. Repeat until the water runs clear, and be sure to place all used water from the flushing process in a sealable container, just as you would dispose of old coolant. At this point, you should replace any worn clamps and hoses as necessary.
Step 8 - Add coolant
The ideal coolant is a mixture of 50 percent antifreeze and 50 percent water. Distilled water should be used as the minerals in tap water can change the properties of the coolant and prevent it from functioning properly.
You can premix the ingredients in a clean container or inject them directly. Most tanks hold about two gallons of coolant, so it's easy to gauge how much you'll need to use.
Step 9 - Bleeding the Air from the Cooling System
Finally, the air trapped in the cooling system needs to be bled out. With the radiator cap open (to avoid pressure build-up), start your engine and let it run for about 15 minutes. Then turn on your heater and turn it to high. This circulates the coolant and allows any trapped air in it to dissipate. Once the air is removed, the space it occupied is gone, leaving a small space for coolant, which can now be added. However, be careful, the air released from the tank can come out and be quite hot.
Next replace the radiator cap and use a rag to wipe away any excess coolant.
Step 10 - Clean and Discard
Check the twist plug for any leaks or spills, discard rags, old clips and hoses, and disposable drain pan. Now you are almost done. Proper disposal of old coolant is just as important as disposal of used oil. Once again, the smell and color of old coolant are particularly attractive to small children, so don't leave it unattended.