1. Can the EGR valve be detached from the iron part to which it is attached? Doesn't appear to be any way to separate the two.

2. Will the EGR valve diaphragm, or any other part of it, be damage if the part is soak/submerged in a solvent?

I need to clean it, darn thing is filthy. Lots of dry powdery carbon trash but lots of greasy black sludge too. Degreaser and oven cleaner aren't getting the job done.

 

I never tried to completely disassemble mine. But heavily hose it with carb cleaner. Works for me done it twice on this rig over last 3 years doesn't seem to have harmed it. My father-in-law turned me on to doing the carb cleaner thing and he's done probably since EGR were equiped on vehicles.