The coolant hose is a critical part of the automotive engine. Because an internal combustion engine runs so hot, a fluid called coolant is needed to circulate throughout the engine. The coolant basically picks up and carries the heat with it into the radiator, where cooler outside air dissipates the heat. The hose is therefore needed in larger sizes to carry coolant into and out of the radiator, as well as in smaller sizes along the intake manifold.
Whether it is large or small, coolant hoses are usually made of thick, tough rubber hosing, as it must withstand fairly high temperatures. Even so, they need to be checked regularly, and replaced every four or five years as a preventative measure. Signs that a coolant hose is at risk of bursting while you drive include the rubber being overly stiff or soft, bulges in the hose walls, or tiny surface cracks on the outside of the hose. Often, however, there are no signs that a hose is weakening, which is why most mechanics recommend that people replace their hoses every four to five years, or before driving the car cross-country.
When replacing a coolant hose, it is important to be sure to find the right parts for the job. Although you can buy coolant hose in bulk, most modern cars have molded hoses, which means that they are factory formed to curve a certain way, or to make difficult 90-degree turns. Buying the correct hose will make the job of replacing it much easier.
Hose clamps are also needed any time you are replacing a coolant hose on your vehicle. Many cars come from the factory with wire hose clamps, or other devices that are difficult to work with, so purchasing new clamps is usually advisable. Hose clamps come in a variety of different sizes, so you will need to be sure that you are buying the correct size to fit on the hose you are replacing.
The old coolant hose can be difficult to remove. The alternating heating and cooling causes rubber hoses to shrink, stiffen, and almost seem to glue themselves into place. You can loosen the old coolant hose by working the flat edge of a straight blade screwdriver underneath the hose, and using that to break the seal, and help pry the old hose off. The new hose should be a snug fit, so you will have to work it into place. Be sure to tighten the hose clamps so that the new hose does not leak.
A high percentage of breakdowns on the side of the road happen because a coolant hose has burst. Regularly checking your hoses, and replacing them as needed, will help to prevent breakdowns and keep your car on the road. Checking the coolant level, is important for the same reason.