[skyship007]

Originally Posted by mjb73

I think they stick due to carbon and abit of oxidization between the surfaces. Never used a blanking plate but have heard good things if combined with a remap to take advantage of the different fueling, but don't know about emissions as that's partly what the valves for.

Nox is nasty stuff to be emitting in a town or city, it was one of the first targets of the EU Greens and the EGR valve & EU standard CAT was the solution (Although the CAT also stops oil ash and some Carbon particles).

The UK MOT regs were upgraded, as was the emissions test and replacement CAT specs for this year. So if you blank off an EGR and then adjust the MAP to allow for it, then it is an MOT or emissions test failure point.
The block was designed to use an EGR & CAT, so if it does not circulate some exhaust gas back when at idle or cold, the CHT falls which increases Carbon deposits in the cylinders and exhaust system.

You clean the EGR with Carb cleaner and toothbrush (Not your own!), BUT when trying to get the valve to budge, Volvo say that dripping rust solvent along the edge of the manifold works better than Carb cleaner.