Their worst enemy is oil. If it gets on the hose, it should be wiped off immediately. If the hoses are not properly secured, they will rub against the surrounding components, which will eventually lead to pinholes.
When checking the oil and electrolyte levels, also inspect the cooling system hoses. Check the tightness of the clamps every three months or after a long period of fast driving. If the clamps cut too deeply into the hoses, move the clamp along the hose or replace the hose. If the hose becomes stiff or cracks begin to develop, replace it immediately.
If a hose ruptures, stop the engine as quickly as possible. Carefully open the hood (there may be a stream of hot coolant under the hood). As soon as possible, place a thick cloth over the ruptured area. Place another cloth over the expansion tank cap and twist it to release the pressure. This will reduce the flow and allow you to pinpoint the problem more accurately. If the problem is with one of the smaller hoses, you may be able to short-circuit the ruptured area. If one of the larger hoses is ruptured, surgical tape or electrical tape may be used as a temporary measure. A more drastic temporary measure is to cut the hose at the ruptured area and insert a piece of metal tubing, securing the hose with two clamps. This device will hold the fluid well until you can install a new hose.
Never pour cold water into a hot engine if it is not running: this is the surest way to cause cracks in the cylinder head. If there is enough coolant in the system, you can pour cold liquid, adding it to the hot one.
Finally, if a hose bursts, you need to find out the cause before taking any action. The burst may be due to the hose being old or neglected. In this case, nothing more than replacing the hose is required. However, if it was a new hose, the cause should be found out immediately.
How to distinguish low-quality hoses
Both the upper and lower radiator hoses do hard work in adverse conditions. They are subjected to pressures of up to 1.5 atm. At temperatures often exceeding 100°C, they must pass about 30,000 liters of coolant per hour - all this is a reason to monitor their condition.
Swollen hose
A good test for a hose is to feel it for softness and porosity. Often these defects will show up as swollen spots on the hose. The most likely cause is exposure to oil. A hose can burst at any time when it is hot and under pressure.
Cracked hose
Cracked hoses are caused by simply looking at the hoses but not feeling them to see if they are solid. Such a hose has cracked to the cord and can crack anywhere.
Wear of the hose end (due to weak clamping)
Loose clamps are often the cause of damage to hoses and the cooling system. The tube-hose connection wears out, and fluid leaks out when the engine is hot.
Dirt in the cooling system
Dirt, rust and scale in the cooling system will cause wear on the inside of the hose. This can be felt on the outside as a soft or thin spot.
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