Keep an eye on the temps and see. Its a good value cooler but only really for dual core CPUs for overclocking but the 2500K does not run that hot so it may be OK. If ypou have not bought the cooler yet then get the 212+ as its much better.
I have a tx3 on my i5 750... and while it isn't the best cooler, I've still managed to OC a bit. My CPU is stock @ 2.66Ghz and I've managed to OC it to 3.25Ghz, while still maintaining idle temps at low 20's and load temps in the mid 50's.
While it's not the best cooler, and I would have suggested others on the i5 2500k... if you already have it may as well try it out. As Simon mentioned, just keep an eye that your temps don't get too high and just see what you can do with it. That's half the fun anyway.