Squeaky belt

I own a 1985 Thunderbird with a 3.8 V6 that has about 5000 miles on a rebuild Jasper engine.

About 6 months ago the harmonic balancer went out and ever since then the belt squeaks (might be more of a chirp) when cold. It will go away after about 5 min of driving but may continue if a very cold day.

I replaced the belt 5 times, had every component connected replaced, (power steering pump, tension pulley, Alternator) the only part that is original is the air pump (smog pump?).

The belt has been tightened, loosened. The power steering pump pulley has been adjusted, I even scoured up the water pump pulley with a grinder for extra “bite”.

All the above made the squeak go away for a day but quickly comes back.

I removed the belt and ran the engine, no squeak. I turned each pulley, no squeak. I even used an old mechanics trick of rubbing a candle on the belt; the squeak goes away immediately but comes back quickly.

I get a slight vibration at about 1000 rpm?s that I think is related to the harmonic balancer but my mechanic says there is little we can do about that.

I am at wits end. Can you suggest what else might be causing the squeak?

Please help, this is driving me nuts!