is there a way to adjust the tension pulley assembly or maybe it needs replacing??
It seems to have moved and is no longer holding the belt you can pull it back outwards and it will hold but not tightly so not sure ...just know that truck will not start if pulley housing slips inward leaving no tension on the belt

 

welcome to df.

its not adjustable. if it won't stay tight - the spring inside is likely broken and the whole thing needs replacing.

check advanceautoparts.com, and get the dayco brand. get the discount codes from priceblink.com (code=A124) to buy online and pickup in store. you can get about $10 off $30. you might have to add a roll of shop towels or brake cleaner to get up to 30.

 

Make sure it is installed correctly. It is keyed to the engine block, and if not there correctly, it cannot tighten. If that is good, then as dhvaughn stated, the spring is likely broken.

 

I have had them be frozen in position. Some penetrating oil and rocking it back and forth may free it up.

 

thinking the spring is bad....it is the original part so guess it was a good one to have lasted my hubby driving the truck since x-mas 1999.//the only pulley that has been replaced was the idler pulley and that was bout 4yrs ago
Thanks for everyone's input