This is about my gf's 96 Nissan Sentra. I've tried other places on
the net without satisfaction. I have an 88 GTA and have posted here
before with success.
Anyway..... In the 96 Sentra, the oil filter bypass hole in the
block is wide open all the time, and a spring can be seen just loosely
lying in it. I don't know how long it has been broken. The car started
making clacking noise from the engine about a year ago. (low oil
pressure, maybe). Her oil pressure idiot light now comes on when hot
and idling. I just discovered the wide open bypass hole a week ago.
The question is : Does having the bypass wide open all the time
affect the oil pressure at the head ? I would guess NOT, since
whether the oil goes thru the filter or the bypass hole, it still ends
up at the same place, the head, correct ?? Maybe if the bypass valve
were still intact the oil pressure in the head would actually be
LOWER, since the filter and the bypass valve would be resisting the
flow of oil.
I hope I am wrong. I hope by replacing the oil filter bypass valve
(which Nissan refers to as an "oil pressure regulator" valve !! ) I
will get some increase in oil pressure at the head and valves, and the
clacking will go away.
ntw, I've had the oil pressure tested, and it is at ZERO when hot and
idling, and only goes up to about 15 psi when reved to about 1500 rpm.
Thanks for any info !!!