How would you check the oil pump to see if its bad...how do you change it? on 2005 Ford Expedition

It's knocking real bad...,

Asked by for the 2005 Ford Expedition
2 answers
POSS TO LATE TO REPAIR IF IT HAS A KNOCK.
if its making a noise then chances are you spun a bearing but to check the oil pressure remove the op switch and install a gauge to check pressure