944684 Volvo.Penta Hollow screw

Introduction
Table 1
Revision History
Revision Summary of Changes
02 Additional comments added to the "Solution" section and changes in belt tension chart table.
01 Additional comments added in the beginning of "Solution" section. The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
8N-6717 V-Belt of 8N-6700 V-Belt Set may fail on certain engines. The modes of failures are as listed below:
Belt worn out
Belt slippage
Belt cut
Negative ride outWhen the number of belts in the drive is more than a set of four, current 144-0235 Belt Tension Gauge has limitation to measure tension in all the belts. This results into improper tension in the belts causing premature wear of belts.Solution
Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.
Caterpillar is aware of this problem and is recommending the below interim action.Tension values for new and used belts are given in Table 2.
Table 2
Belt Tension Chart in Hz
New Belt Tension Used Belt Tension Field Service Check Tension
Min Max Min Max Min Max
Frequency 62 66 55 59 41 46 During commissioning, check and adjust the belt tension to a frequency between 62 to 66 Hz (value given under "New Belt Tension").Note: Value given below "Used belt tension" to be followed if number of hours on belt is >10 hours.Follow the below instructions, when experiencing the belt life time less than 1000 hours:
Check for any misalignment of belt pulleys. Adjust if necessary using "Straight Edge" tool.
If worn out replace the belts with same part number. Always replace all belts as a set.
Use Caterpillar tool 491-2178 Meter (BELT TENSIONER) to set the belt tension in frequency as per Table 2.
During every Preventive Maintenance (PM) service, check the belt tension. Reset/adjust the belt tension to the value "Used Belt Tension" given in Table 2, only if tension falls below the value given under "Field Service Tension Check".Note: Follow the recommended tensioning procedure given below.Recommended Tensioning Procedure
Follow the below recommended tensioning procedure:
Never set belt tension when the belts are hot.
Set the belt tension to appropriate value as per Table 2, as applicable to the belt age.
If the belt is brand new, set the belt tension frequency to "New Belt Tension" value as given in Table 2.
If the belt is more than 10 hours old, set the belt tension frequency to "Used Belt Tension" value as given in Table 2.
Ideally run the engine for five minutes to break in or the belts to be seated.
Allow the belts to cool down.
Reset the belt tension after Break-in to "New Belt Tension" value for brand new belts or to "Used Belt Tension" value if the belt is more than 10 hours old.
During subsequent visits, check the belt tension. Reset / adjust belt tension to "Used Belt Tension" only if the observed tension value falls below the value given under "Field Service Tension Check".Note: Caterpillar recommends checking tension in all the belts to verify that the lowest belt tension falls into the acceptable tolerance range. Tension variations between the belts can theoretically vary as much as 40 Hz on the higher side.