The elastomeric components of the dampener turn vibrations into heat. If the heat can’t be dissipated, the rubber will fail over time. This is why you will see vents in either the wheel well liner or under tray.
The outer or inner inertial mass rings can crack and cause the ring to separate from the dampener assembly. This is rare, but still a possibility on some vehicles. When this happens, a lot of surrounding components can be seriously damaged, like the radiator.
- Deterioration of the rubber
The materials inside the dampener will slowly degrade over time due to ozone, flexing and heat. On most vehicles, the dampener will last the life of the vehicle. The rubber of the dampener should not have cracks, bulges or shrinking.
- Oil leaks
The natural enemy of the harmonic dampener is oil and other fluids. A leaking crankshaft seal can coat the rubber or elastomeric parts of the dampener and cause it to deteriorate. Also, items like leaking valve covers, power steering pumps and A/C compressor oil can cause the rubber to swell, shrink or crack. Fluids can also cause the bond between the metal and rubber to weaken.
- Installation errors
A dampener should never be hit with a hammer. This could damage the internal components. Always use the correct tools to install a dampener. Not using the correct tools can damage the dampener and the crankshaft. The most common installation error is using the center bolt to press the dampener onto the nose of the crank. Chances are you will strip the threads due to the force required to seat some units.
- Removal errors
Always use the correct procedure and tools to pull the dampener from the vehicle. To replace the timing belt on most vehicles, the dampener must be removed. The most important thing to remember is to never put pressure on the outer ring or try to persuade it with a hammer.
- Engine troubles
It is possible for a dampener to be damaged by an engine that is misfiring because the forces at the crank have changed. But the problem could be that a mechanism, such as a misbehaving balance shaft or an item on the rotating assembly, has failed.
- Transmission trouble
The mass of the flywheel, flex plate and/or torque converter are on the other side of the rear main bearing. If these parts are out of specification, they can cause an imbalance in the crankshaft for which the dampener might not be able to compensate. Ask the owner if any transmission work has been performed recently – chances are either the wrong parts were used or they were installed improperly.
- Wrong belt
A belt that is too tight can cause not only stress on the accessory belt drive items, but also on the harmonic dampener due to the extra tension.