have a small few drops at a time each nite leak from under the general area of the oil filter, oil seems to be on the wire that runs along the edge of the oil pan. I rubbed finger around the oil pressure switch and no oil but I think the wire that goes to the with about 8 inches away has oil on it.

how does the oil pressure switch fail- around where it screws in (dry on my car ) or does it leak onto the sending wire, I seem to have oil on the wire.

 

Here's a picture of the front Crankshaft Position Sensor (CKPS) harness wire carrying oil the lowest point to drip.



Here's a picture of the oil pressure sender switch after I replaced it as part of a major engine reseal project. ..



Here's a video of a guy changing a leaking oil pressure switch in the link below.

---> https://www.youtube.com/watch?v=FkUuXtkGWng


::

If you don't have a long socket to remove the sender switch, parts stores like Advance Auto sell one specifically for oil pressure switches.

 

how does the oil pressure switch fail?
- around where it screws into the block (dry on my car )
or does it leak inside the boot from the center of the switch onto the sending wire, I seem to have oil on the wire.

 

The video shows a switch that appears to be leaking from the plastic top. I would clean up your boot, switch top, and wire then monitor for a leaks. I have not seen a factory installed switch leak around the threads at the block

Sent from my Z998 using Maxima

 

Doesn't the switch have an O-Ring?

CS, Your work is B-E-A-U-T-I-F-U-L.

Perfection is ART!

 

Thank you KP. The switches I've removed all used teflon tape on the British Standard Pipe, Tapered (BSPT) threads that screw into the block. The metal body of the switch seems to be stamped around the plastic switch body.
There is a Permatex thread sealer that I've seen people use -- though I've not tried it. I've not encountered an o-ring on a Nissan switch thus far.

I use BWD Intermotor oil pressure switches exclusively as original replacements.

 

post 2 has the 1st picture labelled "ckps wire harness...."

- question" is that wire hooked electrically with the oil pressure switch circuit in any way? it looks like it iS the oil pressure switch wire in picture 2. that is, is the wire harness for the oil pressure switch only or does it then go to the ckps?
-----
and if the oil pressure switch was intermittent would that cause the engine to turn over but not start?

 

The picture label on PhotoBucket comes from a folder of pictures put together for reworking and rerouting the Crank Shaft Position Sensor (CKPS) and Oil Pressure Sensor (OPS) harness rework. The CKPS and OPS wires were re-wrapped and placed in a new conduit. The new conduit was routed above the oil filter to keep oil from spilling onto it during an oil change. Here's the link to that thread ---> https://maxima.org/forums/4th-genera...ss-rework.html

The OPS and the CKPS harnesses split at a Y so the individual wires can be routed from a single harness. That harness runs along and up the rear of the engine to connect to the main harness above the timing chain cover. You can see the Y in the picture below just above the wiring clamp arrow. Wiring insulation on the CKPS and OPS wires keep them from touching inside the conduit.

I do not know if an intermittent OPS problem would keep the engine from starting. Personally I have not experienced that issue. Another member may have more information on that question.

 

ok thanks. much clearer to me now.


some off topic- does the 4th gen have to have an "ok"from the ops for the engine to start??

 

Another member may be able to "chime in" and provide a definitive answer to the question.

However, my first experience with an OPS on a different 91 model Nissan, that coincidentally shares the same switch that is used by the 4th gen, did not experience a problem starting when I had the sensor unplugged to run an oil pressure test. One way to test this would be to unplug the OPS and try to start the engine.

Though some years earlier, I actually had a 280zx mechanic tell me that low or no oil pressure would cause the fuel pump to stop running to keep from damaging the engine. So I also question if an OK signal is needed for engine starting or running.

SIDE NOTE: We have plenty of other issues and items that can cause an intermittent hard to start issue documented in recent threads.

If you have an intermittent "hard to start" problem we can approach those threads and solutions.

 

That last pic, the engine looks brand new!

 

You should see some of his other photos! I'm sure there are operating rooms that have more filth in them than are on his parts. His board name should be Mr. Clean, heavy on the Mr.

I consider myself somewhat neat and tidy but CS is in a league of his own. Love his attention to detail, an inspiration to all

 

yet all i can see is the beat to hell drain plug bolt

 

Thanks guys. It's not about being a show car but for maintainability over the long haul. Being a daily driver, it picks up plenty of dirt from the road.

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