SD begin affecting OLED display
Pins 4 and 5 are the I2C pins that belong to the built in I2C peripheral on the Arduino. You have to put your CS line for the SPI SD card on a different pin. 

EDIT:
The answer above is relevant to the Arduino ATMega328-based board, not ESP8266-based NodeMCU board. This answer is not relevant to ESP8266 or NodeMCU with regard to hardware I2C, as the ESP8266 does not have a dedicated hardware I2C peripheral.