EA82 Engine Vibration

[peterf]

My 92 Loyale (recently purchased) has a very distinctive engine vibration
starting at about 65 mph/ (guessing 3500 rpm). I can best describe it as a
consistent cycle (frequency) of about 1.5 seconds and decreasing in
frequency proportional to an increase in rpm. This probably make very little
so let me just say that it feels exactly like a bad harmonic balancer. It's
definitely a harmonic vibration beginning at the speed I mentioned. Do
Subaru's have vibration dampener problems? Is this a good diagnosis on my
part? TIA

peter

 

[johninKY]

The answer to your question I believe is no. Check the bolt that retains
the balancer for tightness. Possibility the timing belts were recently
changed and the bolt wasn't properly torqued. Is the vibration present if
you just rev the engine out of gear? A broken engine mount could be the
problem. Another is a tire with a broken belt.

 

[peterf]

Thank you that's a good point. I will check the torque. I'll need to check
the no-load condition and see if it present. I'll post the results.

peter

 

[peterf]

Well it most definitely is engine rpm related. I haven't checked the torque
yet but will soon. Any other thoughts on this?

 

[johninKY]

Flexplate may be cracked if an automatic.

 

[peterf]

Thanks, yes it is an automatic. Can you tell what the flexplate does and
where it's located?

 

[johninKY]

Engines with a manual transmission have a flywheel. And engines equipped
with an automatic will have a flexplate. It's that thing the torque
convertor bolts to. Normally this part never fails but will fail
sometimes after the engine and transmission has been separated because the
bolts holding it to the crankshaft where not torqued enough.