Did you know that the number 1 reason for vehicles being towed comes from broken belts and busted coolant hoses? That’s why most hose manufacturers recommend replacing hoses every 4 years regardless of mileage. Belts should be replaced every 5 years or 50,000 miles. The incidence of failure rises sharply after the fourth year of service for hoses and fifth year for belts. The reason it’s recommended to replace hoses at this interval is that rubber hoses deteriorate with age. Tiny cracks develop in the rubber which eventually cause hoses to split, blister or leak. Oil contamination and atmospheric conditions can accelerate the process. Engine vibration and motion can cause hoses to wear if they are too short or rub against other parts. This applies not only to coolant hoses, but to fuel, vacuum and emission hoses as well.
A visual inspection can often help you discover bad hoses. Pinching or squeezing hoses to check for age cracks, brittleness or softness can also help locate hoses that need to be changed as well. However, neither technique will reveal all of the hoses that might need replacing because hoses wear as much from the inside out as they do from the outside in. A hose that appears okay on the outside may actually be on the verge of failure because of internal deterioration. According to research done by one hose manufacturer, internal corrosion caused by electrochemical degradation is the primary cause of cooling system hose failure. The coolant acts like an electrolyte and allows a current to flow between engine and radiator. (You can actually measure this with a digital volt/ohm meter) This causes micro-cracks to form inside the hose which eventually leads to pinhole leaks and the weakening of hose fibers.
As far as belts are concerned, heat and mileage are the main causes of wear. Every time a belt passes around a pulley, it bends and flexes. This produces heat which hardens the rubber over time. The wear process is greatly accelerated if the belt is loose and slips which also causes squealing. The additional friction between belt and pulley will make a belt run hotter. After millions of journeys around the pulleys, even the best drive belt begins to suffer the effects of age. Rubber begins to crack and fray and the internal cords become weak and brittle. You cannot always determine a belts true condition by appearances alone. Any belt that is obviously cracked and frayed should be replaced. With many of today’s bandless belts, there is no outside cover to peel loose and show the belts deteriorated condition. A belt may appear to be like new on the outside, yet be on the verge of failure because of weakened separated cords inside.
When a belt is replaced, it’s important that the belt be properly tensioned. While many vehicles today have automatic belt tensioners, one should still check for proper tensioning. If too loose, the belt will slip and wear quickly. If too tight, it may damage internal cords as well as overload shaft bearings on the accessories it drives. A belt gauge that measures actual tension is the only sure way to know if a belt is tensioned properly.
Few people replace belts and hoses before they fail, yet they could save themselves a lot of unnecessary grief and expense if they would. Why not stop by Mark Martin’s Auto World for a FREE belt and hose inspection today!
