Those cracks...crap rubber. Not able to take the tight radius of the idler pulleys without coming apart. IOW, no elasticity left in them.
As a test, I =bet= you can bend that belt with your hands, in your hands, away from the groves, and watch it CRACK right in front of your eyes.
Lg
Most of them do have them (M40, M42, M43, M44, maybe others). They are called "Vibration Dampers" in the parts lists.
Forgive me if I am repeating someone but -
Do you drive the car hard? Redline or high RPM's? Do you have a clutch fan? Have you verified that it disengages properly?
Blake
Nope. Wife drives car. M44, 4-cyl engine is smooth at all rpm.
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