I've used them a bit, but not on a rad.
A few things to consider.
- The cheap threaded insert tools suck. I've seen a ~$25 Harbor Freight one get broken on the first try at using it. The one I've used at work is ~$125 or thereabouts. I have seen people install them without a tool, using a hardened bolt and a locknut, but it is an ugly/ghetto way to do it and won't always work. You could well wind up with one stuck in there all crooked.
- A threaded rivet will leave a lip. Even the 'low-profile' ones will leave about a 1mm gap between your rad and fans. Don't know how much that might affect cooling efficiency. Perhaps you could alleviate it by using a phobya/xspc/etc rad gasket.
- The depth of an M4 threaded rivet prior to tightening/bulging it in is a concern. I've not used M4 threaded rivets but I would imagine they would be 6-8mm deep or so and the tool will need to thread all the way into it and then a little bit more than that. Seems like you might well wind up hitting the fins in most rads.
- You would have to drill the hole in the rad larger in any case. I suspect an M4 threaded rivet would need a ~7mm hole to fit into. If you're going to drill it larger in any case, I'd just tap the M3 threaded hole out to M4 and be done with it.
Better yet imho, I'd personally just stick with the M3 screws it was made for. They work just fine for me in my Alphacool rads. But that's just me.
Edited by Unicr0nhunter - 12/2/13 at 10:56am