I pulled out all my intercooler piping and cleaned it all out, my question is, is there any way to clean service the recirculation valves? As when I was cleaning them the small U shaped hose was filled with dank as. Water that smelt like it had been there for some time? Luckily I've cleaned it all out before putting the fresh motor back in just just curious do old recirc valves fail and can get I do any thing to prevent it?
If i was you id replace the old recirc valves as with age and wear the can leak even on idle or not stay closed as building boost which was an issue i had with them. I replaced mine with turbosmart kompact bovs piston type i got recirc ones at 34mm outlets. They sound great and actually seem to make a bit of difference. They also fit right where the old oem ones sit. There only around $160 each.
The alternative to replacement is to rebuild them for a third of the price http://www.rgsperformance.com/produ...-rebuild-kit-for-nissan-z32-300zx-twin-turbo/
I would be worried about rust around the diaphragm's edge, giving a wash with soapy water then liberally applying a silicone or other rubber approved water dispersant is about the best you're going to get though. Make sure the chambers are still both air tight before you put much work into fixing them up.
