Belt tensioner will not rotate to release tension to remove belt

Hi Danny, my apologies for taking a week to respond back to you, but I have little to no time for myself since I've been taking care of my parents who are 90 and 94 years old 24/7 going on six years now plus trying to squeeze in time to fix my car. It's been overwhelming to say the least. At this moment they're both napping, so I'm using this opportunity to reply. I wanted to thank you for responding so quickly to my question about the tensioner. I was about 98% sure the tensioner was shot, but wanted to verify it from a professional tech. Also, thanks for the information and pictures. I've been wrenching for 53 years and worked for GM dealers for 26 years in parts department. But this is the first tensioner I've come across that retained its load when going bad, I do have another question for you though about my surge tank. My OEM tank was a first design tank with only one vent line. It's n/a anymore from GM or aftermarket. I had to get the second design tank which has two vent tubes, so I capped off the second tube with rubber vac caps. Since they're somewhat soft I used two caps, 1 that fit the tube dia and 1 that fit over the first cap
and hose clamped but I'm concerned that they will not hold the pressure or will fail from the heat and coolant. It's 15psi. Would plastic welding the end of tube closed be sufficient? Thanks, wrencherhead (Mark) 1996 Cavalier 2.2L TH125C

Hi Danny, don't know if you got my reply from last night so I'm writing it again. First off my apologies for taking a week to reply but I'm a 24/7 caretaker of my parents who are 90 & 94 so time for myself is little to none. Thanks for your quick response about my tensioner. I was about 98% sure the tensioner was shot. Although I'm not ASE certified I 've been wrenching for about 53 yrs 26 with GM dealerships in parts so I'm quite knowledgeable & experienced to include my own ground-up restoration on my 69 Camaro to building my own rotisserie. Anyhow I have another question, the OEM surge tank with 1 vent tube is N/A anymore, only the tank with 2 vent tubes, so temporarily I capped off 2nd tube with vac caps. Since they're soft rubber I placed t to fit tube dia & a 2nd one to fit over 1st cap & hose clamped but I'm not confident that it won't fail due to 15psi, heat & coolant. Would plastic welding the tube end be sufficient or do you have a better suggestion? Thanks wrencherhead. 96 cavalier 2.2L TH125C

Hey Danny. Just noticed there was a second answer from you on my surge tank. I'm going to plastic weld tube end. I'll feel more confident it will be a permanent fix. Thanks for advice.
Wrencherhead