Initial Inspection and Diagnostic Overview
Inspection and Verification1. Verify the customer's concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of the mechanical concerns apply:
- All of the accessories should be rotatable by hand in the unloaded condition. If not, inspect the accessory.
- If any of the accessories are damaged, have a worn or damaged bearing, or internal torsional resistance above normal, install a new component as required.
- NOTE: If fluids get on the drive belt (including power steering fluid, engine coolant, engine oil or air conditioning system lubricant), clean the drive belt with soap and water and thoroughly rinse with clean water. A new drive belt does not have to be installed if no apparent damage has occurred.
NOTE: If the drive belt tensioner arm does not rotate freely without binding, the drive belt tensioner is worn or damaged.
If the drive belt is outside the installation wear range window, install a new drive belt. A drive belt that is too long will allow the drive belt tensioner arm to go all the way to the arm travel stop under certain load conditions, which will release tension to the drive belt.
3. Inspect for drive belt cracking/chunking/wear.
Under severe operating conditions (high temperature, low humidity), drive belt rib cracking can occur at less than 96,000 km (60,000 miles). Drive belt rib cracking (cracks across grooves):
- is not a reason for concern.
- has no detrimental effect on drive belt performance.
Cracks parallel to grooves are acceptable.
The drive belt is still perfectly functional until rib chunking occurs. Drive belt chunking is where the rubber material actually chunks out between the cracks. A new drive belt should be installed if chunking occurs.
V-Ribbed Serpentine Drive Belt With Cracks Across Rim
V-Ribbed Serpentine Drive Belt With Chunks of Rib Missing
4. If the concern(s) remains after inspection, determine the symptoms. Symptom Related Diagnostic Procedures