Causes of Failure of Ribbed Belts and the Solution
Hardened, polished flanks

| Diagnosis | Solution |
|---|---|
| Incorrect tensioning | Change the belt, adjust tension correctly |
| Tension member of belt damaged by incorrect fitting | Change the belt, fit properly |
Uneven wear on ribs

| Diagnosis | Solution |
|---|---|
| Pulleys are not aligned | Examine the drive. Line up or, if necessary, replace any non-aligned pulleys, change the belt |
| Substantial belt vibrations | Check the tension. If necessary, tighten or change the belt |
Running noises from belt

| Diagnosis | Solution |
|---|---|
| Insufficient tension | Tighten or change the belt |
| Belt past its useful life | Change the belt |
Cracks/separations in belt body/ribs

| Diagnosis | Solution |
|---|---|
| Belt tension is too high/low | Change the belt, adjust tension correctly |
| Belt past its useful life | Change the belt |
| Foreign matter | Change the belt |
Crack in the belt after a short running time

| Diagnosis | Solution |
|---|---|
| Tension members damaged as a result of incorrect fitting | Change the belt, fitting it correctly |
| Belt excessively tensioned | Change the belt, adjust tension correctly |
Dirt accumulation on the belt

| Diagnosis | Solution |
|---|---|
| Leaks in the engine or engine compartment (e.g. escape of oil, antifreeze etc.) | Repair leak(s), change the belt |
Damage to the back of the belt

| Diagnosis | Solution |
|---|---|
| Back idler pulley defective (sluggish, surface damaged, e.g. by foreign matter) | Change the belt, replace the back idler pulleys |
Unacceptable wear of belt ribs

| Diagnosis | Solution |
|---|---|
| Pulleys/idlers/assemblies defective (sluggish) | Replace pulleys/idlers/assemblies, change the belt |
| Pulleys not aligned | Align or replace pulleys, change the belt |