[Vwdiesel] belt tension

[Pam & Doug Boes]

I have a belt that goes from the crank to the water pump to the PS pump.
Bentley says the correct tension is 3/16". I had just put a new belt on and
it squeeled a lot and was thrown off while I was driving. I figured I must
have had it too tight. No I've loosened the belt twice and it still squeels.
How loose can I go before it will fall off from being too loose. If it
squeels at almost idle and goes away at speed, is that OK?