On the s70's checking the breather box was easy to test with a balloon over the dipstick. However on the later cars this is not always the case. My volvo mechanic tells me it depends on how it is clogged.

I had a 2003 v70 that when it clogged it whistled and had alot of suction.

My mechanic told me the breather box should be tested by a pressure test and should read vacuum, but he won't tell me how. (nice guy)

Does anyone know how to pressure test the pcv this way?

Thanks Madenss