I removed the filter cover on a 3.2 MK1. While cleaning it up ready to fit the new filter I realized that the old filter didn't come out with the cover. When I had a closer look I realized that the spigot that locates the filter in the cover was missing and so was the flange on the base of the spigot meaning that a fair amount of oil was bypassing the filter. Don't know how long it has been like this and how much unfiltered oil has been through the engine. This customer had recently bought the Ranger with a blown head gasket and had another workshop do the job, don't know if they broke it and didn't replace it or changed the oil & filter and in the rush to do the oil change in under 10 minutes they just didn't realise that it was missing the spigot.
I don't know if this is a common thing to happen but thought I would just give everyone a heads up.