Oil Pump Repair/Replace?

[Furgonzo]

So it appears I have a stuck/faulty oil pressure relief valve in my '89 1.7 diesel vanagon. Two times in the past couple weeks, upon start up the oil filter seal has blown, spewing the contents of my engine about the tarmac. I have not checked the pressure as I have no gauge. This one is new to me, so I am wondering if dropping the pan and pulling the oil pump is any more complicated than it sounds. Is the OPRV obvious on the pump and is it replaceable or does one generally swap out the whole pump...I am not sure I can find a new/used pump round my way. Is the OPRV serviceable or when it goes, it's gone? Any thoughts are hugely appreciated.

[ewenmaclean]

If you can get a new pump, it's a fairly easy replacement - once the sump's off, it's two 13mm bolts and fit into the vac pump. It's possible to change the pick-up pipe, but not sure how easy it is to change the release valve mechanism.

I wonder if your problem is oil constriction after the filter though - unlikely, but worth checking before condemning the pump - what's the pressure like at the head?

[Furgonzo]

Thanks for the thoughts. I wish I knew the pressure at the head. I don't have a gauge. How would I go about checking if the constriction is after the filter? The filter is new (between first and second gasket failure), weather was coldest of the year on the 2 days it happened (~0º C) - van hasn't seen weather below freezing since I've had it. Van fires up fine and idles OK, but give it gas and the oil filter gasket immediately fails - doesn't break, just pops out of its groove. Others I've spoken to say the symptoms suggest a faulty relief valve, but twould be nice to not have to pull the oil pump...