Originally Posted by 85chedeng300D

does anyone out there knows where can i get a replacement blow-off valve diaphragm for an '85 300D turbo??? on california models, i am referring to the vacuum element/diaphragm that is located on the forward side of the intake body of the turbocharger that is usually connected to a blue/light-blue vacuum hose. it is secured by (3) 10 mm bolts almost looks like a thermostat housing. i think it is important because i'm guessing, what it really does is, if the wastegate lets go of the HOT EXHAUST AIR to prevent turbo from overspeeding, on the other hand, this blow-off valve lets go of the COLD INTAKE AIR and recirculates it to prevent the turbo from lagging. therfore air intake is regulated and prevents too much or too high intake manifold pressure when the engine don't need that much amount air to burn with diesel.
for some reason, mine was puctured and tried everything to vulcanize it but it keeps leeking and my vacuum system, especially transmission shift is affected. i already tried to install a diaphragm out of a dodge neon SRT4, which is a little bigger and shallow but i'm not happy with it. it fixed the vacuum leak but i'm not sure if its really working right and not doing what it supposed to do. it doesn't have that high-pitched humming sound like it used to do before it broke.
can anyoune tell me where can i buy one of this or any domestic car that will match this particular part???