I’ve always assumed my crankcase ventilation didn’t work. When I bought the car the P.C.V. hose was missing (along with the smog pump) and the nipple on the breather box looked pretty gummed up, but the car ran so I just told myself I'd fix it eventually. I’m finally getting around to it now, but I realized I’m not really sure if it’s broken or not, it could be functioning fine (exhausting its gases into our atmosphere instead of recirculating them due to the missing hose) and its chronic oil leak/hemorrhage could just be the result of it being 35 years old. Is there any way to test if it’s working or not? Also, where exactly is the hose supposed to go?

 

It’s worth adding that my B20 has its intake manifold and exhaust manifold on the same side, so my breather box is very accessible.

 

There should be a hose from the side of the breather box to the intake manifold in order to run the crankcase emissions through the cylinders again. When the hose or the breather box stops breathing because of all the gunk, some shade tree mechanics simply remove the hose and allow the emissions to vent into the atmosphere. That doesn't pass smog inspection of course. But, if no smog test is required, everybody's happy (except EPA).

Also if your oil filler cap has a hose, that goes to the air intake filter box.

 

Ah, I see where it’s supposed to connect now. Is there anywhere I can go to find out how to clean my breather box? I pulled it off once (it’s only being held on by one allan bolt) but after that I just stared at it for a while and couldn’t decide what to do.

 

The breather box can usually be cleaned up with engine degreaser or carb cleaner. Maybe ream it out with a wooden dowel. In worst cases it can be replaced.