how to check the oil pressure as follows;

the oil pressure level depends on a variety of factors (engine speed ,oil temperature, oil pump rotor clearance etc.) the measurement should always be carried out with the oil at a temperature of 80degc. the oil pressure should be 1.8bars at idle speed and 2.4bars at 2000rpm. however, the maximum pressure should not exceed 5bars at engine speeds in excess of 2000rpm.

follow this and if its still only 15ibs then you have problems