Oil pressure too high – Filter burst

Hello, I have a hearty problem there. With my V40 last Thursday the oil filter has burst. I got a new one and just Friday morning, so one day later it’s also a fug. my sled now stands for the friendly examination. since I find out that the oil pump builds up too much pressure (over 5 bar) and the master tells me that I need a new one. So now I have a new oil pump but that also has 3.8 where you can only have about 2.8. the engine has been cleaned and the problem keeps itself stubborn. now I have learned that the young have to take apart from the friendly engine to solve the problem, because it can just as well be the whole engine over. until now it is only 800 fleas that I should pay. if they build the engine apart and then it is ok, then 2000 fleas, but if the engine is there I need a new one that is not quite so cheap. Who can help with something know or similar to the experience?