Thread: Harmonic balancer fail

If an idler pulley jams, it puts tremendous stress on the harmonic balancer. Remember there is no mechanical connection between the inner and outer, only the rubber ring that is bonded to each. Mine seized at speed and destroyed the belt. There was no way rubber bonding was going to survive that amount of torque. I guess yours was the same.

Originally Posted by !Brumby

Bought a 2002 TD5 in August 2012 to replace the TDI. 127,000 on the clock and clean and straight, including underneath. In November, the harmonic balancer went to pieces, took out the fan as well. It was repaired, drove 1000km and engine stopped at low revs and would turn over slowly but not start. Idler arm jammed and stopped belts turning, which stopped engine. Got idler arm fixed. Drove a couple of thousand km towing a camper trailer. Went well until a couple of weeks ago when I noticed a rattle and a klunk after stopping the engine. Mechanic says rubber in the harmonic balancer is coming apart, maybe from uneven pressure by aircon compressor. Has anyone else had an issue with this kind of problem? Mechanic says the design of the harmonic balancer is "fatally flawed". Love how it drives when it runs well.

The fatal flaw was probably your mechanic not making a simple check of the other belt driven components when the balancer buggered up the first time.
Was the new balancer genuine or after market?

When I siezed a idler pully bearing the harmonic broke the rubber and the belt burnt through.

I'd sugest do the idler pully assey if non ace + the adjuster assey.
If one goes the other won't be far behind
Also given your dramas I'd be doing the only bearing left, behind the fan in the timing case.
Check the air/cond, alt, and ace pump if fitted.

Go genuine for the lot if possible, cheap ones fail way to quick