To avoid an untimely breakdown, check your hoses regularly. The radiator and smaller-diameter heater hoses can fail suddenly, but there are usually telltale signs that can warn you. To check the hoses, first look for softness and swelling. A good hose will be firm, flexible and resilient. A bad hose will be spongy.
Replace any hose that is soft or bulging. Since oil and grease deteriorate and soften rubber, be sure to wipe down oily hoses and get any oil leaks fixed right away. Also check hoses for hardening and cracks. Squeeze the hoses, since sometimes that's the only way to get a crack to reveal itself.
On hoses that run near hot or moving components, be sure to check for chafing and localized heat damage. This type of damage often hides underneath the hose, so inspect carefully.
When replacing a hose that has clamps, be sure to use new, screw-type clamps. Many newer vehicles use quick-connect fittings. Your Haynes manual will tell you how to disconnect these hoses
In addition to the cooling system hoses, there are many smaller hoses running through your engine compartment. Most of these are vacuum hoses that operate fuel and emissions-system components. Check these hoses for the same telltale signs as the cooling system hoses. Also look for kinks and softness that will cause the hose to collapse under vacuum.
A failed vacuum hose does not usually result in catastrophe - the symptoms are usually subtle. You might notice a change in the quality of the engine idle or that the Check Engine light is illuminated. By carefully inspecting the vacuum hoses, you can sometimes fix a nagging driveability problem. Keep in mind that old vacuum hoses can become disconnected easily, and it's sometimes difficult to remember how they’re connected. During inspection, try not to disconnect the hoses and mark the connection points carefully when replacing the hoses.
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