sudden reduction in oil pressure

[grannyknot]

Philip, I don't know about that, I would argue that all of the oil goes through the filter so that is the place to put your rare earth magnet, big particles are going to fall to the bottom of the pan anyway. When I cut open a used filter that I have had a magnet on there is always a black paste of metal particles, now the paper membrane of the filter might have caught them all but maybe not. But you really have to make sure that the magnet can NOT come off the filter before the filter change, you can imagine this big charge of steel powder hitting the pleats all at once, some of it is going to get through.

[Dave WM]

Well for now its on the drain plug. I have the new pump coming wed, and I picked up a Nissan OE gasket, pretty cheap only 50c.I like to use OE gaskets when I can get them. I can get some more rare earth type magnets at the local surplus store (sky junk) soon when I get the courage to drive up I4 in central Florida... they have a good selection of magnets and always interesting junk to look at.

[Captain Obvious]

Have you checked the oil level?

 

 

I'm Captain Obvious, and I approve this message.

[Dave WM]

10 hours ago, Captain Obvious said:

Have you checked the oil level?

Yes, as well as changed it and new filter.

 

I'm Captain Obvious, and I approve this message.

 

[Captain Obvious]

Haha! Well I had very little doubt, but someone had to ask!

[Dave WM]

NP you would not be CO if you did not ask! any other ideas on the cause of a sudden drop? I am thinking about pulling the pan to investigate further, and maybe remove the crank journals one at a time to look at the bearings while its off. I am assuming the biggest cause of oil pressure drop is thru the crank bearings... IF something bad happened there.

[Zed Head]

You need to verify that the pressure actually dropped first, right?  The gauges are very old.  Not going to last forever.  And the sensors are known to fail.

Seems like, no offense, you're forging ahead based on a tenuous assumption.  Potential for much wasted time and effort.  Unless, of course, you're just a little bit bored.

[Dave WM]

I put a manual gauge on it, maxed out at about 50-55, on my spare engine I was getting closer to 65 with the same mech gauge

I am getting the same results with two different senders. The mech reading seems to relate to the gauge (gauge and mech read the same approx. psi). I just expected closer to 65 on cold oil.

I also checked the resistance readings using the same sender on both engines, the spare engine was consistently lower resistance (higher pressure).

Of course never having taken a reading with the mech gauge before noting the problem means I am just assuming the pressure is actually lower than it was a week ago. (ignoring the electrical gauge).

 

Edited November 6, 2019 by Dave WM

[Dave WM]

OK ignore me when I complain...

I had a NEW sender that I had yet to try (I used the one from spare engine which was new a year ago, but not the same brand as the old one (BA) that was in there.

I put in the NEW BA sender and I am back to getting the same kind of pressure INDICATED on the gauge. Regardless of all the stuff I posted above. So the new plan is going to be to install the T connector since it is on the way, and confirm my readings. I have a NEW pump coming today, I may install just for the sake of science... but will def wait until I get that T in there and get a REAL reading of the oil pressure. My guess is I have NO problem...

Sorry for the red herring.

[Captain Obvious]

Huh? Who said that?  

Seriously though, I hope this whole thing was a non-problem and will resolve with no internal surgery required.

[Dave WM]

Got the new pump, came in a box Nissan part number and label on the box from an ebay vendor as an Nissan OE part. However, no made in japan or hitachi markings the case. Only a

K9 and a A22 stamped on it. I wanted to take it apart and look over the rotor etc... but it is not coming apart (removed the 2 10mm screws) easy so I backed off. I did put some fresh oil in it just to see it move oil around.

So now I don't know if I have a cheap china knock off part of if this is what the current Nissan pumps look like.

 

 

[Dave WM]

You all know I am going to try it out right? If for no other reason than pulling my old pump out to check it over.

Edited November 6, 2019 by Dave WM