200tdi cyclone breather question
I have an oil leak at the rocker cover on my 200tdi. I have renewed the rocker cover gasket with no change in the leak. It's definitely coming from the rocker cover and not from the o ring at the breather, etc. I also made sure it wasn't over torqued when installed. Compression is around 340psi per cylinder with no more than about a 7% difference between cylinders. These numbers are not as high as some 200tdi's I've seen which is usually 400+ psi. True mileage of the engine is unknown however the truck pulls great and does not smoke excessively.
I wanted to check the cyclone breather and I followed the instructions in the workshop manual. Attached is a picture of the instructions. It says to draw a vacuum from the bottom hole and to plug the two upper holes. It states that unplugging either of the two upper holes should release the diaphragm and the pressure. I made sure it was clean before testing. I can only get vacuum to build if I plug both upper holes, which seems normal. However, I can only get the pressure to release if I unplug the hole going into the rocker cover; unplugging the hole that goes to the intake changes nothing. Is this how it is supposed to operate, or is the breather potentially bad? Thanks for any help.