Volvo: Squealing sounds while engine idles, timing belt tensioner, crankshaft pulley

Question
QUESTION: Hey Ray- My '93, 940 with over 268K miles makes a loud squealing sound from the engine compartment  & I've noticed cabin vibration at idle or low speeds. However, the faster I drive the quieter the sounds. I recently replaced the water pump which emitted a grinding sound, but all other components (pulley's, alternator, timing belt, engine belts, etc.) are the same as when I bought the car about 5 years ago. I read where the crankshaft pulley can make such a sound on the b230 engines. Where do you recommend I look first to correct this problem most economically?

Thanx,
Pro
ANSWER: Pro,
Make sure that the crank pulley is good. Also listen carefully to see if maybe the noise is coming from behind the timing cover, that could mean there is a bad idler pulley.

---------- FOLLOW-UP ----------

QUESTION: Ray, Thanx for your prompt response as usual. When I was younger, I'd probably tackle many auto repairs myself, but age has brought wisdom & lack of patience so I now defer to those who make auto repair their vocation. Is there a way I can check my cranksaft pulley? Also, is the idler pulley the same as the timing belt tensioner? Plus, can I run my engine with the timing belt cover off (to see if all is functioning)?

thanx,
Pro  

Answer
Pro,
Use a socket wrench on the pulley nut, a chain wrench as a counter hold on the outside of the pulley. As you hold the counter hold try and turn the center nut watching the pulley if it turns inside the outer belt grooves it is bad. Tensioner and idler same thing. Go ahead and run the engine without the cover.