Volkswagen Repair: 1997 VW Vento problems, crankshaft pulley, vw vento

Question
Hi,
I have a couple of problems,hope you can help.
I have a 1997 VW Vento GL,automatic,Fwd,2.0L
(1)Sometimes when driving between 35-40 Kph my Rpm needle sticks at 3 and my speedometer needle sticks also even tho I have my foot pressing the gas...this happens for a couple seconds good and then it frees up...it sounds awful???(2)When I am in traffic and I turn on my AC the Rpm needle jumps wildly up and down????(3)I notice also that my temp needle sometimes move from the halfway mark which is 90 and settles at 100???....Is that normal for VW?
 Lots of questions I know...any help greatly appriciated.
 Thanks...Jason  

Answer
Hi there, Jason.  I don't know what a Vento is, but am familiar with the ABA 2.0L engine, and the FDF automatic transmission.  I have a feeling that the serpentine, multi-accessory belt is squealing, and that is the awful noise in traffic...am I right?  If you have not had the serpentine belt replaced recently...ie., within the last 30,000 km, then start with that, but I think there is something else going on too.  It kind of sounds like the belt tensioning device is not working correctly either.  Don't spend the money to replace only the belt.  Get both the tensioner, and the belt, and replace them at the same time.  Before you spend all this money, though...look at the belt, and feel the tensioner.  If the belt is not uniform...on the back side, not the ribbed side...in its' appearance then the tensioner is likely to blame.  Most serpentine belts get shiny on the back after they have an opportunity to wear a while.  If there are alternating shiny, and then dull spots along the belt then the tensioner is no longer turning freely, and will soon seize up completely, and your crankshaft pulley will just melt through the belt.  See if these things help the behavior of you car, Jason, and let me know through this forum.  Good luck.