Changed the oil and filter, and now the oil pressure is a too high. I used 15W-40 NAPA fleet universal oil, for cars and Diesel engines. API SN service for cars, and a string of diesel oil engine service codes a mile long, the high zinc stuff. And the oil filter I used was a premium 99% efficient filter (versus the standard 93% eff cheap filters), I think both I looked at were STP, the one I bought I think was an STP premium, and it had the orange silicone antidrain back valve like K&N uses. AZ was out of stock on the K&N filter and I will never use the junk Fram, paper/cardboard et al, filters. So the problem is the oil pressure is now running 50-70 PSI, since the oil change. It was 30-40 psi using 10W30 and 10w40 summer and winter according my daughter.

I suspect the filter, and not the oil but that assumes the Oil P-sensor is sensing oil pressure between the pump and the filter!!!! So I need to know where it is plumbed in on these beasts, before or after the filter? Thanks.

 

Did you overfill it? Normally the it's pump, filter then gauge at the end before the pump

 

Sorry, but that sounds contradictory? "Normally the it's pump, filter then gauge at the end before the pump" You lost with "before the pump"???

 

Gauge/pressure sensor should be at the end of the line, so before the pump

 

That is impossible, the oil filter and the oil pressure sensor must be after the oil pump, not before.

 

It’s possible the quality control on that Napa oil is out. If you’re concerned you might want to change the oil to a recognized brand 10-40 and use a filter you’re used to. Small price for piece of mind. Just my two bits.

SD

 

No, the oil is, was fine. It is a great oil, not an off brand by any means. It is high ZDDP zinc, and better cleaning than most, universal API SL car spec and meets all old diesel API specs, very hard to find anymore.

I use it on my diesel Franken-Jeep, 1981 Nissan SD22 diesel I slapped into a 1985 Jeep Cherokee years ago. , no issues. The engine is a beast!!! No oil pressure issues.
My daughter's #%$@*&$^%-other wasted $$$ having Jiffyscrew-n-lube change the oil and filter to what they had been using, It made no difference, so it is the sensor or wiring/connection that changed when the oil and filter was first changed. Not surprised as it has other wiring issues....too

Thanks. Never did a 100% sure answer to the 1995 location question. But the answer is academic now. I thought the high efficiency 99% filter might have been the issue.

 

Er, ugh, no. Start with the pump, now insert the filter, now add all the things that are supplied by the oil, now the gauge/sensor, now to the front of the pump, closed system.

 

OK, the pressure sensor on your engine is mounted on the block at the back of the engine. Check the A-1 Auto You Tube demo showing how to remove it. So to answer your question, after the oil passes through the oil pump, it goes through the filter, through the engine block then pressure is measured at the head prior to the oil being released to the rockers. It looked pretty easy to remove except you had to climb on top of the engine to reach the very back. Hope that helps. Note: Just took a closer look. The sensor is mounted to a boss machined into the back of the block.

SD

 

Not sure if the original poster is interested in this but there is a very good discussion of the Oil Pressure switch and how to replace it. Keep reading because they also talk about the screen beneath the sensor.

"07+ DIY Oil Pressure /Switch Replacement May 16,2013 " I accidentally fount it in the section called " Tahoe & Suburban DIY and Useful Threads". Enjoy.

SD