I had some pulleys given to me, apparently bought thru ebay, the ones with the green colored seal (GMB brand/ korean made) (the bearings on my car say Japan on them)..would anybody know what the expected safe useful life of these bearings to be ...perhaps the same as subaru at 100K+mi or maybe less...

Edited January 6, 201115 yr by Petersubaru

I have run them for 50k now in my 2.2, they seem to be of the same quality as the stock ones. I would still change them at your timing belt interval, but wouldn't really worry about them otherwise.

GMB is oem certified stuff for Subie's. I wouldn't worry about them until your next belt change. 110k miles

I've put many of them on, no problems.

 

On used engines that I've pulled, I've seen only one failure and I have no idea how long it was on. I've seen many failures of the Black stock Subaru idlers, as they are often ignored and run to failure.