So my BOV for my turbo has been leaking.... for quite a while. At first, I thought it was the O ring (which actually the O ring was messed up so my initial hypothesis was correct). I replaced the O ring, but the BOV still leaks mainly at idle and deceleration. Any ideas what it might be? My BOV is a Tial Q, and I'm thinking it might be the spring but I'm not for sure. Any ideas of what it might be?(hoses and everything else is good too).

 

They have different springs for different idle vacuum ranges. Maybe yours is too soft?

http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

 

That's what I was thinking but this BOV has been on for a while can vacuum idle in/hg change over time or does the amount usually stay the same?