Harmonic Vibration at specific RPM

timothyd · **Joined:** Wed Feb 20, 2019 2:58 am **Posts:** 90

I recently have a new vibration in the engine that is RPM specific, about 1500-1800 and happens both in park and while driving. It sounds harmonic and seems to be worse when cold. I recently changed the engine mounts and did just change the fan clutch and swapped to the plastic fan.

WWDiesel · **Posted:** Sun Sep 10, 2023 9:59 pm

timothyd wrote:

I recently have a new vibration in the engine that is RPM specific, about 1500-1800 and happens both in park and while driving. It sounds harmonic and seems to be worse when cold. I recently changed the engine mounts and did just change the fan clutch and swapped to the plastic fan.

Remove the serpentine belt and start the engine and see if the noise goes away or stays.

Could be your harmonic balancer is bad and the rubber bonding is separating allowing it to rattle under certain conditions.
Physically grab the harmonic pulley and see if it is loose or has any movement in it at all. There should be NONE!

These guys rebuild them if you need it repaired as they are no longer available anymore new in North America.

Damper Doctor:> http://damperdoctor.com/

Harmonic Vibration at specific RPM

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