Vehicle arrived here friday night, low oil pressure symbol displayed on dash, checked oil level it seemed to be overfilled, as we have serviced this van recently we knew it had not been overfilled at that time nor has the customer added any oil since service, as customer had to drive to Glasgow at weekend in the van we changed the oil and added to correct level, assuming we have some oil dilution with fuel going on.
Vehicle has come back today with high oil level again.
What are the common faults which may cause this with this engine?
Injector gallery seals?

Any suggestions would be welcome, Thanks, Fil