last night on the way home from the girlfriends, the noise my dump valve makes suddenly changed, it was a clear change of sound from one gear change to the next........
it has now gone from a very crisp tsshhhhhh to a its got a cold sounding tcchhhhoooo
ive had the dump valve off today and the diaphram looks fine, there was a small amount of oil inside which i cleaned out and the noise did change slightly however its not back to how it was
anyone got any ideas
ive checked all the pipes aswell and i cant find anything, car is boosting as it was before and doesnt seem to be running any different
i know sometimes the springs bed in and change the sound but this was a sudden change in sound....