Oil Pressure Issues in SKODA OCTAVIA II 1.6 TDI 2010 After Oil Cooler Replacement

SKODA OCTAVIA II 1.6 TDI 2010. So from the beginning.After a long journey, the coolant began to decline rapidly and the liquid level indicator light came on, after refilling I could drive about 30 km and the problem repeated, the reason was the oil cooler, and more precisely the oil filter housing, so black, because on the water channel where the gasket is placed there was a chipped edge that holds the gasket in place. After replacing it with a used one with a mileage of about 10,000, a problem with the oil pressure began, namely after heating while driving, the oil pressure light turns on, after the engine is turned off and after restarting the indicator light goes out, but after adding gas above 1500 rpm. before replacing this cooler, I had no problem with this pressure, even with a damaged one and with this fluid leakage
refrigerant.

the oil level is ok, but why after replacing this cooler, there was no problem before, because when I drove to the mechanic, the engine was hot and the indicator did not light up, there was a valve on the spring in the filter housing, maybe this could be a reason?

You have something wrongly screwed, a damaged filter housing or a wrong filter, o-rings.
It will show what exactly was mentioned.

Or the oil pressure sensor is not connected.

Hey buddy and what was to blame?