Air Filter Box

[mikra]

My air filter box is under slight positive pressure at idle speed making the diaphragm valve on the box blow out slightly (3litre diesel) I think it should be under suction.
Any ideas

[Hazzo]

mine would suck your arm off, have you got a spud in the exhaust pipe, that doesn't sound too clever mate I'd be dismantling all the breathing, intake and exhaust to see whats up, do the rocker to turbo breather pipe too it gets full of gunge as does the intake manifold if your EGR is operational. H

[mikra]

Air Filter Box

Starts and Runs ok only obvious symptom is the positive pressure,no gung or spud in exhaust any more ideas