Engine 01 01–00 Safety Precautions 4. Check for tensile breaks (breaks in the cord body). Cuts in a belt are usually caused by for- eign objects in the pulley, or by prying or forcing the belt during removal or installation. Safety Precautions in this section apply to all procedures within this group. 5. Check for uneven ribs on serpentine belts. For- eign objects in the pulley will erode the under- cord ribs, causing the belt to lose its gripping power. DANGER When working on the vehicle, shut down the en- gine, set the parking brake, and chock the tires. Before working under the vehicle, always place jack stands under the frame rails to ensure the vehicle can not drop.
Failure to follow these steps could result in serious personal injury or death. 6. For EPDM belts, check the belt for material loss, which causes the belt to seat further down in the pulley and to ride directly on the pulley tips. See Fig. 1 . 7. For Neoprene belts, check the drive belts for cracks. Small irregular cracks are usually signs of an old belt. 01–01 Engine Drive Belt Inspection 8. Inspect the pulleys for excessive play or wobble. Excessive play or wobble indicates a failure of the pulley bearing. Check for belt squealing or squeaking. Replace the bearings as necessary. NOTE:
If it is difficult to distinguish the location of a supposed bearing noise, place a stetho- scope on the component being checked, not the pulley, to isolate the area from outside interfer- ence. Worn or loose drive belts may cause engine over- heating or loss of alternator power. Excessive ten- sion, or too little tension on the belt may result in ex- cessive and premature belt wear or accessory bearing failure. Serpentine belts are retained by a belt tensioner that requires no tension adjustment. Replace the drive belt if any conditions described below are found. To inspect a belt, gently twist it to view the belt sidewalls and bottom. 9.
Inspect all pulleys for foreign objects, oil, or grease in the grooves. Belt Tensioner Inspection IMPORTANT: For EPDM rubber drive belts, do not rely on cracking as an indicator of belt wear. EPDM rubber drive belts resist cracking better than Neoprene belts. A better indicator of wear on EPDM belts is material loss. On belts equipped with a spring tensioner, belt ten- sion is automatically adjusted. Check that the ten- sioner is holding tension on the belt by inserting the end of a breaker bar in the 1/2-inch square hole on the forward face of the tensioner, and rotating the tensioner away from the belt.
When the breaker bar is slowly released, the tensioner should return to its original position. The tensioner should rotate smoothly with no binding. If not, see Group 01 of the 122SD and Coronado Workshop Manual for replace- ment instructions. Belt and Pulley Inspection 1. Inspect the belt for glazing. Glazing is repre- sented by shiny sidewalls, and is caused by fric- tion created when a loose belt slips in the pul- leys. It can also be caused by oil or grease on the pulleys. 2. Check the belt for ply separation. Oil, grease, or belt dressing can cause the belt to fall apart in layers. Repair any oil or coolant leaks that are affecting the belts before replacing the drive belts.
Do not use belt dressing on any belt. 3. Check the belt for a jagged or streaked sidewall. Jagged or streaked sidewalls are the result of foreign objects, such as sand or gravel in the pulley, or a rough pulley surface. 122SD and Coronado 132 Maintenance Manual, February 2016 01/1