The PCV is probably on the opposite valve cover. All that would happen with this doohicky being disconnected is that air would flow through the oil fill hole, through the engine, and into the PCV, which is pretty much what normally happens. The PCV valve will prevent the manifold vacuum from becoming depleted, regardless of whether the crankcase is open or closed.



If a lot of oil splashed out of that hole, you may have been running the engine low on oil. Dirt could have gotten in here, but would probably be cleansed through the oil filter. Other than that, there's no way this would cause long term harm. Your emissions problem is something else. Possibly the PCV valve itself is defective, and that's why your fill hose blew off. I'd start by replacing the valve.

I need to recheck how PCV valves work but I believe in the face of an opened end vacuum is supposed to pull the Valve against spring tension and close off the flow.
But, that is in general I have to look up this prticular PCV valve.

It is a push rod engine so there was no evidence of long term oil splash. Although I did smell oil vapor for at least 6 months. Also I seldom drive on the freeway which would reduce the chance of Oil coming out.

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84 300D, 82 Volvo 244Gl Diesel

Your PCV valve operation understanding is correct. Definitely check for vacuum to the valve though and see if the valve rattles. Check that it is EXACTLY the correct valve by part #. Seen excessive oil consumption due to the wrong PCV valve.

As for other sensor/computer concerns etc. I'm going with no related trouble codes unless the air intake was pulling in a lot of oily fumes. Did the air filter element look excessively oily?

There isn't a sensor to measure crankcase pressure so it couldn't have thrown anything off to the ECM.

Consider installing a new seal/grommet in the valve cover, secure the pipe and drive on. FWIW, the 4.3's are VERY good engines.

Good Luck!!!

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