97TDIStu said:
Ok, so what you are all saying is that the tensioner , lever and, pulley near the alterntor at the TOP of the engine is NOT the CAUSE of the problem. It is the EFFECT caused by the balancer ( not to confused with the tensioner puller) . AND this "balancer" is on the bottom part of the belt route on the crankshaft pulley itself? Someone please advise. Am I clear on this?
If you have read this entire thread, as well as the several others on belt noise, you will find that indeed there are multiple potential causes of squeaking noise--anything wrong in the belt drive system which results in the belt loosening can cause belt slippage with the resulting noise.
What several people have found is that, even with a brand-new belt, tensioner spring, and tensioner pulley roller, the squeaking still exists.
If you look at the pictures of the original and new-design harmonic damper pulley back on page 2 of this thread, you will see a difference in how the torque is transmitted from the crankshaft to the belt. In the original design (shown on the left), the pulley is built into the outer ring (the actual dampener weight) which is coupled to the inner part of the pulley (which is bolted to the crankshaft) VIA A THIN RING OF RUBBER. When the rubber gets old, and when it's cold, the rubber slips a bit every time one of the cylinders fires, causing a squeak. When the rubber warms up a bit, it expands and the slipping and squeaking stops.
With the new-design damper, the pulley is DIRECTLY COUPLED to the crankshaft, and the dampener weight is INSIDE the dampener, still coupled by the rubber ring. There is no possibility for pulley slippage with this new design, and hence is no squeaking! When the vehicle is cold, there is a high load on the alternator (recharge battery, run coolant and engine glow plugs, defroster fan, rear window defrost, etc) which really puts a load on the serpentine belt.
So it's actually the rubber ring in the old-design dampener pulley which is making the noise, not the belt.
Does this help to explain things a bit? Like I said before, this is only one possible cause of a squeaking noise, but it was definitely the source on my vehicle.
It's also very important to clean and relubricate the two bronze bushings (inside the aluminum bracket which holds the alternator and A/C compressor) which guide the belt tensioner arm--on my car, the grease had all dried and the arm was literally stuck in one place--it was so bound up that even the tensioner spring couldn't overcome the friction. I removed the rod (helps to remove the airbox first), cleaned out the bushings with solvent and foam-tipped 6" long swabs, replaced both the seals at each end of the rod, and lubricated the bushings with high-temperature silicone grease (sylglide), being super careful not to get any grease anywhere near the belt or pulleys.
'Tis the season for the squeak-squeak-squeak!
