Tensioner pulley

I'm getting some growling under the hood. It seems to be coming from the tensioner using a stethoscope. I picked up a new pulley but when removing the old one something just doesnt feel right. The bolt didn't pop loose, it feels kinda mushy like I'm striping it. I got a quarter turn out of it & stopped. The bolt doesnt appear to have backed out at all.

I'm wondering if this is a reverse thread bolt? It would make sense since the pressure to remove the belt is counterclockwise & you could possibly loosen the bolt when attempting to relieve the tension.

Any body know about the reverse thread question?

Thanks.

Well it looks like it is a left handed thread according to a search on the GP board. Rats!!!
The bolt seems to be holding solid but now I'm afraid to back it out the correct way. I may have given it a half turn in the wrong direction with a cheater pipe on my rachet. Next time ask first right?